Head Questions Answered

[Vigilante]

For all my brothers that have ever questioned or wondered about Cobra Heads:

Ported 99/01 heads are far better than stock 03/04 heads.

Stock 99/01 heads would be better than ported 96-98 heads.

Ported 03/04 heads would be the best (except for the FR500s)

Porting is the great equalizer and can make most any head better than the next, well, except for making a 96-98 head better than the 99/01s or the 03/04s. The newer heads will always be better than the 96-98s.

Also, the newer heads use a much better intake manifold. The 96-98 intake is not a good design and I can't think of an rpm range or use for which it's suited.

If you are changing heads, go with the either of the newer heads. I personally would go for ported 99/01s because they are available and much cheaper than the 03/04s.

As for that B-head stg 3 port job providing 45hp gains, that's BS. Maybe a port job combined with aggressive cams. That goes for the stg 2 port also, another BS. If the engine is n/a and they should not make the ports bigger, tehy are already too big. Enlarging the ports will reduce low rpm power and put the peak power rpm out of reach for any stock shortblock. The port should only be reshaped and the bowl areas cleaned up, especially on an engine that is not going to see over 7K. Definitely no gasket matching as this will increase port volume significantly.

Now, if you do have ports that are enlarged greatly, you have to run cams that can use that port volume efficiently. The cams would have a lot of duration and a narrow lobe center which would result in a lot of overlap. Not what you want for the street. This would require at least a 4.56 gear because you would have no power below 5k. JimsSVT's car has heads that have been polished and cleaned up only. His cams are aggressive but don't ahve too much overlap and he makes 380rwhp. This proves you don't have to go crazy with the porting on B-heads

The problem with that "oh so sexy" intake is that it stinks. The design is just awful and in no way do the inner workings of it resemble a power producing intake.

I stayed with my B heads because I'm a cheap bastard. I learned from that but have since found a way to make them work in a "not so bad" way on my n/a motor. It's compromise that doesn't have to be made with the C or 03/04 heads but nevertheless, its still a compromise and cost me more in the long run. Still got me over 350rwhp with unported B heads though.

Sticking with B heads will be a compromise on an FI engine also. You will still not have the low end provided by the newer heads nor will you have the increased power provided by the newer heads. The Bs will be closer up top but at the low end will be much lower. Now, if the supercharger of choice is a positive displacement blower then the shortfall of the B heads could be overcome by the added boost in the low rpm range, but then again, none of the positive displacement blowers for the B heads have an intercoooler so boost would be limited due to intake charge temps.

So, with the vortech and B heads expect a soggy bottom end like you have now and that cannot be overcome by adding more gear because you ahve a supercharger.

With newer heads and the vortech you can expect more power at the low end and also the upper rpm range.

It all comes down to money you have to spend, how much power you want and where you want the power to be.

Source:
http://www.svtperformance.com/forums/sn95-cobras-24/336979-cobra-heads-help.html#post4315910
http://www.svtperformance.com/forums/sn95-cobras-24/643202-cylinder-heads-faq.html

'B' Heads:
http://s881.photobucket.com/user/yfz162/media/IMG_0193.jpg.html
http://s53.photobucket.com/user/zoom1523/media/100_1467.jpg.html

'C' Heads(99-03+ look the same, all are C heads):
http://www.terminator-cobra.com/images/99 & 01 head.jpg

Combustion Chamber CCs:
B heads...52cc
99/01......54cc
03/04......52cc
navi........53cc
FR500.....53cc

CFM:
valve lift....96/98........99/01.........03/04
.050.........39/34........40/34...........40/32
.100.........79/71........88/74...........88/68
.150.........114/97......120/102........118/97
.200.........144/119.....152/123........151/120
.250.........172/132.....178/138........178/135
.300.........194/138.....197/138........201/150
.400.........217/144.....218/143........221/163
.450.........225/145.....222/145........229/166
.500.........231/146.....225/145........233/169

Notice the difference in the port shape between B heads and 03/04 heads(or C heads). Two distinct ports(Square Port gets covered by the IMRC until 3250 RPMs) versus one large oval that splits into two. Another downside to the B heads is revealed here, they get dirtier in the Square port faster than the Round, due to the fuel injector only "washing" the round port. Gunking of the IMRCs is a common problem as well. So switching to a later head or simply making IMRC deletes will reduce maintenence as well(but you lose much needed torque, to optimize these heads the IMRCs should actually open closer to 4000rpm).

^^^No way another noob should EVER ask if a damn M112(03/04 Eaton Supercharger) will fit on 96-98 cobra.

Mach 1, 03/04 Cobra, Aviator, Marauder, Navigator
Intake: 184 deg @ .050/.397" lift (measured duration)Exhaust: 196 deg @ .050/.397" lift
114 LCs
The lincoln intake cams I checked have 184 deg duration also.

96-98 Cobra
intake PN#s F6ZE-6A270-AB crosses to F6ZZ-6250-AA
F6ZE-6A271-AB crosses to F6ZZ-6250-BA

Intake: 202-204 deg @.050/ .397 lift (measured durations varied between cams with the same part number and the primary and secondary lobes have the same durations and LCs)
Exhaust: 196 deg @.050/.397 lift
114/114 LCs

99/01 Cobra
Intake: 200 deg @.050/.397 lift (measured duration)
Exhaust: 196 deg @.050/.397 lift
114 LCs

FR500 (M-6550-T46)
intake: 212 deg @.050 /.472 lift (measured duration)
exhaust: 208 deg @.050 /.472 lift (measured duration)
109 LCs

GT Cams: (actual as tested numbers, not Ford specs)
Intake: 189 @ .050"/.424 lift (measured duration)
Exhaust: 190 @ .050"/.448" lift (measured duration)
The centerline is up for debate as this set tested at 122/118 but I think Ford states the LCs as 114/114

Cobra R cams:
Intake: .515'' lift 212 deg dur @.050
Exhaust: .468'' lift 212 deg dur @.050


B/Swirl Port: (93-97 Lincoln Mark VIII, pre 99 Lincoln Continental, 96-98 Cobra).
The only production Ford head with two (square primary, round secondary) intake ports per cylinder, these swirl port castings arrived first in the ’93 Lincoln Mark VIII. Aptly named, due to the way they promoted the incoming air to swirl into the combustion chambers. full sink.
Through the years these heads have proven themselves to be excellent performers for power adder applications--since their tremendous combined intake port cross sectional area and volume (when combined, a full 55cc more than any other 4.6L head design) provide for exceptional power production in the upper regions of the tach. Ironically, it’s those same big, beautiful, twin ports that also prove to be the B head’s largest inherent design flaw. The extra intake port size has a tendency to kill low/mid rpm intake port velocity and power production—hence the use of Ford’s first IMRC (intake manifold runner control) intake on the 96-98 Cobra. By allowing air to reach only one of a B head’s twin intake valves, velocity, and therefore low/mid range torque production was restored in situations under 3250rpm. Later head designs are clearly superior in this regard, which happens to be the one of the most important considerations for those wanting a stout street motor.
There is also some controversy over the single fuel injector/dual intake port setup. Some claim insufficient air/fuel mixing because of the compromised design, however, others contest that the ability to make 1000+rwhp with only minor porting and some form of power adder is testament to the contrary. Whoever you believe, there is little doubt that even after as little as 8,000 miles, carbon and other deposits tend to form on the secondary ports, causing a major airflow impedance, as there is no fuel present to clean them. B heads feature a somewhat small stock exhaust port that really hinders flow in power adder applications. Major gains from porting come with a quality valve job, some pocket and lots of exhaust work. There really isn’t a lot of material to remove from the intake ports themselves.
The Bottom Line: B heads aren’t the best choice for a naturally aspirated street motor. In order to really shine, they need to be paired with a power adder and a short block that can sustain high horsepower and rpm levels. These, the oldest heads, may still be a great choice for full race applications.

Stock Intake Choices: ‘93-‘97 Lincoln Mark VIII, ‘96-‘98 Cobra.
Aftermarket/Modified Stock Intake Choices: short runner
B head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 107cc primary (square), 115cc secondary (round). Intake Port Entrance: 1.500x1.300” primary (square), 1.660x1.400” secondary (round), Valves: 37mm Int., 30mm Exh.

C/Tumble Port: (99/01 Cobra, 99 Lincoln Continental).
These second-generation Ford DOHC heads feature a single intake port per cylinder with a smaller cross sectional area that boosts incoming airflow velocity compared to previous years. To understand how C heads earn their “tumble port” designation, try to imagine an Olympic high diver doing repetitive front somersaults before cleanly entering a pool at the bottom. This controlled tumble allows for better air/fuel mixing than in the earlier swirl port heads. The new port design allowed for both substantial increases in midrange torque, and superior horsepower production under 8000rpm when compared with earlier heads. Combustion chamber size is also up 2cc.
The design downfall of C heads, and their larger (5.4L Navigator) cousins, is the relatively flat floor and utter lack of a short turn radius in the throat of the intake port. As such, the incoming air tends to overshoot the valves, making the port think the valves are smaller than they actually are. Some ‘99/’01 Cobra owners reported a “ticking/pinging” noise coming from the drivers side head of their cars. This is due to insufficient cooling around the #6, 7, and 8 cylinders that allowed the valves to overheat and therefore seat improperly. Ford remedied the situation by issuing a TSB to remove and replace the affected heads with a version that featured altered coolant flow.
C heads feature a small exhaust port much like Ford’s earlier swirl port heads, but unlike in B heads, both the intake (throat region) and exhaust ports can see extensive porting work. However, removing too much material from the intake port (mouth region) of a tumble port head will kill velocity very quickly, so make sure your head porter knows what they are doing!
The Bottom Line: C heads remain a viable performance upgrade for those looking for more punch in their street driven 4.6L four valve, without having to pay new part prices for the ’03 DOHC or FR500 versions. The increased midrange torque production and greater overall area under the power curve (when compared to swirl port heads) will enhance the performance of a street/strip driven (8,000rpm and under) modular regardless of application.

Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500.
Aftermarket /Modified Stock Intake Choices: short runner/ported ‘99/’01 Cobra, Sullivan intake, FR500, Aviator
C head dimensions: Combustion Chamber: 54cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.

Navigator: (98+ Lincoln Navigator)
These 5.4L DOHC heads feature essentially the same intake port design as C heads, however they have a much larger intake port volume than 4.6L castings. Despite the fact these heads feature a relatively small exhaust port, the extra intake port volume could be very beneficial in helping fill a motor of greater displacement—think 5.4L. Expect slightly better midrange torque, and sub 8000rpm horsepower production than even C heads, however the larger intake port size leaves a slim selection of intakes to choose from when utilized on a 4.6L block. Forced induction fans take note, Navigator exhaust ports feature a thicker exhaust divider (while keeping the same overall exhaust port size as B,C, and FR500 heads) that allows coolant to circulate through this vital area. Conversely however, the larger divider can also hurt flow by utilizing additional space in the port.
The real downside to Navigator heads, when used on a 4.6L based motor, is the severe limitation they impose on intake selection. The physically larger 5.4L heads don’t leave a lot of room (when installed on a 4.6L block) between them for an intake plenum to sit—though they do bolt right up. Remember that since Navigator intake ports are essentially clones of those of C heads (just on a larger scale), they too suffer from the same intake port flaws that plague the earlier tumble port design--no short turn or floor in the throat of the intake port.
The Bottom Line: The extra port volume the Navi’s possess could be very beneficial in filling a motor with greater than 281 cubic inches of displacement, or in high rpm N/A street/strip or boosted combinations. Fans of boost should remember the cooled exhaust port divider. Lack of intake availability is the real downfall of this otherwise wonderful casting.

Stock Intake Choices: None (4.6L), 98+ Navigator (5.4L)
Aftermarket/Modified Stock Intake Choices: short runner 99 Cobra (4.6L), sheet metal
Navigator head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 184cc, Intake Port Entrance: 2.290”x1.400”, Valves: 37mm Int., 30mm Exh.

’00 Cobra R: (’00 Cobra R)
Cobra R heads are bar none the best Modular heads available today. However, their extremely scare supply makes them both ridiculously hard to find, and unbelievably expensive.
Initial performance results are understandably hard to obtain, however Al Papitto reports that with only 25hrs of port work into the his new ‘00R heads, they have already eclipsed the performance of his old Navigator heads with months of labor in them. These heads feature larger intake and exhaust ports, +1mm larger exhaust valves, and a dry exhaust port divider. Cobra R heads also require the use of a specific valvetrain not shared with any other modular application due mainly to their overall physically larger size. Al also claims R heads have too much port volume for a street/strip 4.6L application; only consider them with a larger 5.4L motor or a serious 4.6L race application paired with some form of power adder.
The Bottom Line: The best heads you can or can’t find for a Modular four valve motor.
You are as likely to come across a set of these Modular “Godfather” heads as you are to be Brittany Spears’ next uterus masseuse. Though based on their performance abilities, you may want to start saving, just in case…
Stock Intake Choices: None (4.6L), ’00 Cobra R (5.4L)
Aftermarket/Modified Stock Intake Choices: Sheet metal
’00 Cobra R head dimensions: Combustion Chamber: N/A , Intake Port Vol.: N/A , Intake Port Entrance: 2.370”x1.300”, Valves: 37mm Int. 31mm Exh.
Stock Intake Choices: ‘00R
Aftermarket Intake Choices: Sheetmetal.

FR500: (FRPP)
The sole “aftermarket” offering of the bunch, these high flow heads feature a modified C head intake port combined with the smallest port volume of the group—it seems Ford meant to design these heads for high performance naturally aspirated applications. With the same small standard exhaust port as most other DOHC heads you will still have to remove a decent amount of material from the exhaust ports. Port entrance shape/size remains identical to C heads so finding an intake isn’t hard. These heads are capable of producing power beyond 8000rpm, where earlier versions of the tumble port castings begin to lose their luster. FR500 heads are prone to the #6,7, and 8 cylinder cooling problems as well. Major intake port differences between these and earlier tumble port heads include a raised intake port roof, and a real short turn radius that better directs the incoming air into the combustion chamber; not over the valves like in earlier versions of tumble port heads. These heads also feature a dry divider in the exhaust port, which allows for greater flow, but also higher temperatures. Though improved, the heads can still use some TLC from a quality porter to smooth the roughly finished and newly implemented short turn radius, and the standard exhaust treatment.
The Bottom Line: Outstanding performance heads, with exceptional low and mid lift flow capability. The FR500s only real fault is that the newer ’03 DOHC heads provide near identical performance capability (much better on the exhaust side) paired with a cost differential that is approximately two-thirds less than the FRPP castings. Still a great choice for any application, the heads readily pair to a wide variety of stock and aftermarket intakes.
Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500.
Aftermarket /Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP/Sullivan carb intake, FR500, Aviator.
FR500 head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 160cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.

‘03 DOHC head: (‘03+ Aviator, Marauder, Cobra, Mach 1, Australian Boss 260/290)
Featuring a nearly identical (though 17cc larger in volume due to the fact that they are also used on the much larger Australian Boss 260/290 5.4L DOHCs) intake port to the FR500 head, but combining it with a newly designed, larger and more rectangular exhaust port, these may be the best all around DOHC Ford heads ever manufactured. The improvements made to the intake port shape over previous years include a raised port roof and the introduction of a short radius turn in the throat of the intake port that helps assure the incoming air charge finds the combustion chamber. For those with a forced induction street/strip motor, these are without question the best heads available, and as with the FR500s, they should produce great power up to and beyond 8000rpm regardless of application. ’03 DOHC heads also feature higher quality head castings from the supplier, which is at least partially responsible for the modest increase in flow vs. earlier castings--chalk that up to Ford’s revised quality control standards.
Early runs of the ’03 DOHC head fell victim to the same #6,7,8 cylinder coolant flow problems as earlier tumble port castings. In mid ’03 Ford made a running revision to the ’03 DOHC heads that allowed for more coolant to circulate through the affected areas. A blue mark on the driver’s side head indicates an updated casting, and there are no additional revisions to the ’04 version of this design.
The Bottom Line: On all accounts these are the best modular four valve heads currently available. They combine the exceptional flow of a slightly larger FR500 intake port with a gigantic new rectangular exhaust port.

Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500.
Aftermarket/Modified Stock Intake Choices: short runner/ported ‘99/’01 Cobra, Sullivan, FR500, Aviator.
’03 DOHC head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.

In Conclusion
Our panel of experts surmised that aside from the nearly unobtainable ‘00R heads, the ’03 DOHC heads are without question the right choice for your Modular four-valve performance application . The combination of a slightly larger FR500 intake port and modified throat region, coupled with a new larger rectangular exhaust port, and a relatively low price (due to it’s widespread use in the Ford organization) makes the ’03 DOHC casting the current head stud of Ford’s Modular stable.
After porting, the relatively small stock valves/seats become the most serious flow limitation; as such aftermarket replacements should be a serious consideration for those looking to squeeze every last drop of performance from their DOHC heads.


Here are a few basic thoughts on the new 3v heads...
With 34.7mm intake valves and a 38.5mm exhaust valve, on paper the '05 3v heads seem to be an excellent street/strip performance head. The 4.6/5.4L heads are identical with the exception of different valves/springs on the 4.6s that allow them to safely rev to 6200rpm. The VCT (when unleashed by a tune) allows for one hell of a nice torque plateau--especially by comparison to earlier N/A 4v DOHCs.

With that being said, with regard to ultimate power production potential 3v heads are still inferior to 4v castings. Curiously, the intake valves on a 3v head are pushed into the side of the chamber, to the point where a stock valve is unnecessarily shrouded. The location of the seats makes it impossible to install larger seats/valves without actually hurting flow on a N/A motor. You would have thought Ford learned something about unshrouding the valves in a small bore motor during the FR500/Big bore programs. Especially since the limiting factors for flow on all DOHC heads are the valve seats/valves The exhaust needs more help, with its single valve, than the intake as well. Both the intake and exhaust ports appear to be fairly nice, and appear to be (I haven't had a set in my hands to confirm this yet) sporting a higher/raised port than 4.6 4v heads. I haven't heard anything about short turn casting quality yet either.
I'm still waiting for the VCT 4v motors

Interesting notes by NA_SVT; 96-98 Cams>99/01 Cams>03/04 Cams and PP 'C' heads>Stock 03/04, Stock 99/01>PP 'B' Heads and PP 03/04>All(but really expensive).

Source:
http://www.svtperformance.com/forum...k-question-wheres-thread-head-comparison.html

The 96-98 "B" heads outflow the 99+ tumble port heads "C" but in n/a for the "C" heads make more power. The "B" heads have cfm but don't have velocity. Hence the secondary port. That's why FI on the B heads shine under boost. For n/a race setup you wanna go with Mach1, 03/04, Navigator, FR500 heads would be the best bet. -Mark

^While this is generally correct there needs to be more understanding of why this is sometimes not true. 'B' Heads have the smallest exhaust flow. It'll cram air in like a fat kid and cake, but the exhaust needs to be opened up when doing a port job. Here is where the problem lies; Everyone knows the fastest 4v is a B headed engine. Its also revving to 9k and pushing 2300hp after hours and hours of porting. Simply put, after extensive race porting and cash the B heads will shine. There is a reason 'C' heads are better for a realistic application and thats because of the perameters of driving around the city and cost. C heads will generate better low and mid range results, thus making it a better head for a street strip application or N/A(and the reason b heads were dropped from production).

Slightly edited due to the tech getting turned into a shit storm:

The 96-98 heads make the best pure race head for NA cars(Other then the cobra Rs) when ported they outflow every other head out the on the intake side, while the 03/04 4v head makes the best boosted head with a very good intake flow numbers and by far the best exhaust numbers.

'B' heads will outflow everything on the intake side. You are partly right about the tumble ports making more power. Under 7000 rpm the tumble port design works better. But above 7000 the Bs take over. That is why I said for a pure race head. The FRPP still will work better then the 99-01 heads or 03/04 NA on the street. You are wrong about these being the best head for boost. That title without a doubt goes to the 03/04 head which was redesigned for the terminator with boost in mind. This head posts far and away the best exhaust flow numbers of any 4V head.

Exhaust is just as important as intake when it comes to looking at heads. An Engine is, simply put, a large air pump. To make power, and make power effectively, it needs to go out just as fast as it comes in. Think of a fireplace, the wood you put in has more volume than the ashes you take out, BUT that doesn't mean you let the ashes sit there because if you don't clean out the ashes, they will pile up eventually cluttering the area of the fire. This is why the exhaust valves are smaller, but too small and you will lose efficiency. Dragsters are known for making power, not making power efficiency like the rest of the world on a budget. There is a huge difference between 2300hp and 100,000's of dollars and 500 hp for the working guy. The 03/04 heads are better than B heads for both N/A AND Boosted applications.

The Intake on a vehicle is another important factor for selecting heads. What really killed the 'B' headed cobras? The intake. High volume, low velocity heads combined with a long runner intake setup is asking for low-end numbers to be butchered. The Engineers tried to solve it with the IMRCs, but they were better in thoery than real world. Again, "'B' Heads love boost" statement comes to mind. Why? FI will help the low velocity problem and because of the high volume make good numbers to boot. So whats the big porblem? I'll just fix my B heads woes with a super/turbocharger and get a sheetmetal intake(which are crazy expensive btw).
The short answer: In-Effecient and making power comes through efficiency.

You are basically going to cover up the fact that you need the air velocity by using FI to push it through. Unless your spinning the motor to 7000+rpms and/or pushing 30+PSI you will be better off switching to a later head design and going from there. Look at the "engines" from the sixties, the goal then was 1hp/ci which is 61hp/liter. Now we are seeing same performance times with better running engines in smaller packages. Why I ask? You guessed it, efficiency. Our new goal is 100hp/liter. The first mods most mustang owners do is add exhaust because it lets the motor breathe. Its one big air pump, get air in and out asap. If cost is keeping you from switching, run it with psi, but just know there is power on the table with 03/04.

The facts are this, B-heads do not outflow any of the other 4V heads in stock form. They are the worst heads for any n/a application...no matter what the rpm is. They aren't even the first choice for thos builders making high hp street FI engines.

Source:
http://www.svtperformance.com/forums/sn95-cobras-24/152684-98-cobra-motor-questions.html

But wait theres more! I see your Intake and head design(port velocity) and raise you valve lift! Ok... now we're getting to the bottom of the bucket. First the old 2v>4v idea. My auto teacher ever told me he didn't understand why you would want more than two valves:dw: The basic idea is that two smaller valves can move more air than one larger valve. In order for a 2v to outflow a 4v it would need impossible lift(mechanically the piston would slap it and blow your motor for the required lift). Anyways, the 4v are better suited for duration instead of lift. In the chart at the top, the 03/04 heads have better flow even at .500" of lift. In order for the B heads to surpass the newer design you would need lots of lift and eventually you will be limited to the extent you can go. The port velocity is so slow, the air does not wish to fill the cylinder as complete and quickly as later heads.

Moral of the story, the b heads are only superior if running very high rpm's with a power adder, in other words a drag car. For a street car the newer heads are a much better choice.

"C" Heads vs 03/04 Heads:

- Ported 99/01 heads can be better than stock 03/04 heads
- Ported 99/01 heads can also be equal to or better than ported 03/04 heads...it all depends on who does the porting

Most n/a motors don't need a complete port job, most motors will benefit from a simple bowl area cleanup.

The difference between these heads is something worth posting. The common idea that, 99/01 heads are for FI and 03/04 heads are better for N/A, is NOT true. The smaller ports hinder, not help, with turbo spooling(which is from expanding hot gas NOT how fast the gas exits the head) or port velocity. Porting can make the earlier heads surpass the newer head design, but only a quality port can and will do this. So PP C head vs PP 03/04 head can actually be equal... to an extent.

Here is something I found interesting:

What cams will you be running? One of the biggest differences in the package is with the cams. The 99-01 cams (in addition to the heads) are designed for more top end power and RPM range, while the 03-04 cams are designed for more bottom end torque. As a result, the engine makes peak power lower in the RPM range. This can be troublesome for those with centrifugal blowers because there's 500 or so less RPM to build up the peak boost, which as we know, comes at peak RPM.

When I swapped to a junkyard aviator longblock (long story), I kept my procharger on it, and my motor actually made about 40 less peak horsepower, but made 30 more HP and 50 more LB/FT of torque than the 99 heads/cams at 4000 RPM, and peak torque came 1000 RPM's earlier in the powerband. Everything was held constant, including the procharger, pulley size, etc.. all except for the longblock and the tune. The tune might have had something to do with it, being that It was very conservative compared to the old tune because I didn't want to blow this one up. But you get the idea.

Homer

What's interesting is the fact that this proves the original statement above, "99/01 heads are for FI and 03/04 heads are for N/A" falls apart. A low and mid-range gain was found switching from C to the later style head, while being choked up top. The C heads had a better peak. Depending on what you can land a deal on, either head can be made equal, but your powerband shape will look different depending on which head you find.

The biggest influence of potential head power comes with the result of a tune. A crappy tune will produce crappy results. Vice versa, A quality ported and tuned C head will blow away an 03/04 head design. Porting/Polishing and Tuning are two areas you cannot skimp in.

Source:
http://www.svtperformance.com/forums/new-edge-cobras-51/625895-99-c-heads-vs-03-04-heads.html
http://www.svtperformance.com/forums/new-edge-cobras-51/582016-what-heads.html

Just wanted to add that the best bang for buck for us SN95 guys is: 99+ Continental C Heads pulled from a Junk Yard, Quality Porting/Polishing, C Head short runner lower intake, B to C Head Adapter by na_svt, B head upper intake and SN95 Cobra intake cams.

 

[97desertCobra]

MODS grab some Gorilla Glue and sticky this!!! All we need are some pics of the heads and the actual cfm flow of each head and I think its a done deal!

 

[mwolson]

Some of the head flow data is on the sheet in the post.

I am in the middle of porting and polishing a set of torn down 03 Cobra heads, so tell me what pictures you want of them and I will post some high res pictures for you.

 

[Vigilante]

Some of the head flow data is on the sheet in the post.

I am in the middle of porting and polishing a set of torn down 03 Cobra heads, so tell me what pictures you want of them and I will post some high res pictures for you.

How about the bottom(the actual bowls) and maybe a shot down ports. Anything else you wanna snap a pic of

 

[b dub]

Can't we just say 03 heads and 96 cams are best and leave it at that?



My head hurts.

 

[Vigilante]

^ Lol, now we have cliffs too.

MODS grab some Gorilla Glue and sticky this!!! All we need are some pics of the heads and the actual cfm flow of each head and I think its a done deal!

CFM flow is in the middle. Its the jpeg image included in the post.

I am so glad you like it! it was time consuming(two hours in the same spot nonstop) but we've needed something like this for a while now. I don't consider it complete yet, but I hope it can be.

 

[mwolson]

You can grab any of the pictures you want from these writeups I have on my brand new, unused 03 Cobra heads off of a crate motor.

Here are the pictures from when I cc'd the combustion chambers: http://www.classictiger.com/mustang/TeksidTerminator/CCing/CCing.htm

Here are the disaasembly pictures: http://www.classictiger.com/mustang/TeksidTerminator/HeadDisassembly/HeadDisassembly.htm

Here are the pictures from port matching the intake manifold: http://www.classictiger.com/mustang/TeksidTerminator/IntakePortMatch/IntakePortMatch.htm

Here are the pictures from the port & polish work in progress: http://www.classictiger.com/mustang...PortMatchAndPolish/HeadPortMatchAndPolish.htm

Let me know if there are any other shots you want.

 

[na svt]

Here are some pics of a set of B heads (for Tabres new build), they're almost done:

 

[Tabres]

:rockon:

 

[Vigilante]

thanks guys, pics have been added. would like to get a set of c heads up to show tumble vs swirl

 

[Toasty]

Here are some pics of a set of B heads (for Tabres new build), they're almost done:

How much were you able to lay back the outer edge of the combustion chamber closest to the exhaust valves?

 

[97desertCobra]

^ Lol, now we have cliffs too.



CFM flow is in the middle. Its the jpeg image included in the post.

I am so glad you like it! it was time consuming(two hours in the same spot nonstop) but we've needed something like this for a while now. I don't consider it complete yet, but I hope it can be.

I can see it now but when I posted earlier I couldn't see it on my computer.:shrug:

 

[98 N/A 4V]

I wish I could have met the engineer who designed the b-heads.......and kick him square in da balls and say thanks for nothing.

 

[na svt]

I wish I could have met the engineer who designed the b-heads.......and kick him square in da balls and say thanks for nothing.

If he had balls the design would have much different.

How much were you able to lay back the outer edge of the combustion chamber closest to the exhaust valves?

That area can be laid back very little on a stock bore engine, but on a Big Bore it can opened up much more at both valves. However, most people when going with a big bore fail to take advantage of this.

 

[97desertCobra]

Reading all of the original post just reminds me how inferior my B heads are:nonono:. Only thing I really like about the B heads is that the B intake looks better than the 99-01 intake. If only we could run the C heads and the B intake.

 

[na svt]

Reading all of the original post just reminds me how inferior my B heads are:nonono:. Only thing I really like about the B heads is that the B intake looks better than the 99-01 intake. If only we could run the C heads and the B intake.

You could run the b head upper on the c head lower. That would allow you to use the stock TB along with the throttle and cruise cables.

 

[b dub]

If you would make that adapter plate.

 

[97desertCobra]

You could run the b head upper on the c head lower. That would allow you to use the stock TB along with the throttle and cruise cables.

Does it bolt right up to C head lower?!?! If so thats what I will do! Not to mention it would make everybody think I'm just running B heads when in reality they are ported 03-04 heads!:rockon:

 

[na svt]

If you would make that adapter plate.

I have one half made.

Does it bolt right up to C head lower?!?!

It will.

 

[b dub]

So you found a new water jet guy?