4.6L to 5.3L swap

[Abneycody]

Hello fellow cobra advocates! I own a beautiful 97 cobra and have decided that it's time to put more to the wheels. This car has sentimenal value to me, so don't bother saying, "sell it and buy a terminator". Trust me, as tempting as it is, this Cobra is my baby and will be by my side till the day I die!

Anyways here we go.. I was recently talking to a buddy about cars and he mentioned that Ford Performance has a 5.3L Modular Shortblock running for around $5,500. I am on about a $10,000 budget, and I will be choosing to go N/A for personal reasons. As fun as it is, I've never liked the idea of leaf blowing air into my engine! Anyways, my goal for the car is to bring it up to 500rwhp.

Does anyone have experience with a 4.6L to a 5.3L modular stroker? What kind of power gains could I expect from just the new block alone? Is there anything I'll have to consider upgrading after having the new block?

I plan to throw in some high flow cams, my BBK long tubes along with my shorty x pipe.

With the new 5.3L block, high flow cams, headers, and a good tune, would I be able to hit my 500rwhp goal?

 

[cbr repsol]

It's a stroker..your going to get more power but with longer stoke cranks you usually get way more torque out of any engine.
It's a leverage thing. Like taking a bolt off with a wrench compared to using a breaker bar.
Lol
I don't think you will make 500rwhp. Your really asking for 600 flywheel n/a your going to have to have the heads ported to really take advantage of larger cams.
Just guessing I think it's going to be mid to high 400 range n/a you might get close to the 500 in torque.

 

[cbr repsol]

I wanted to add I've seen it done but it is not gonna be cheap.

 

[Abneycody]

Thanks for the response! In your opinion, what would be the way to go on getting power out of this engine while staying N/A?

 

[cbr repsol]

Fully ported heads ,larger valves, bigger cams, compression, octane, long tube station.
The stroker will also help .

 

[Mystic-SVT]

If staying with the B-heads you'll need a short runner intake, high compression, cams (I'd talk to someone who knows about cams to custom spec a set and have them degreed), 1-3/4" longtubes, no cats, rev to the moon.

I'd get rid of the B-heads and find a set of C-heads and have them worked over, 1mm bigger valves, FR500 intake or find a short runner C-head intake. It'll still be hard to hit 500hp though.

 

[cj428mach]

Have you driven a forced induction car before? There was a time where I felt Ford was "cheating" or "taking the easy way" by bolting on a supercharger to the Terminators. After having a forced induction car I can't see why anyone would go NA unless you're doing long durations of WOT where heat is an issue. With a blower you can have street car manners with insane power numbers.

I say do a terminator drivetrain swap and if you have the coin upgrade the blower. You can be at 6-700rwhp depending upon what you want to spend with out even cracking the motor open.

 

[cbr repsol]

I'm with the last post.
My stock motor 04 cobra made 552rwhp on just 16 psi on 91 pump. The car was really fast.

 

[Abneycody]

Have you driven a forced induction car before? There was a time where I felt Ford was "cheating" or "taking the easy way" by bolting on a supercharger to the Terminators. After having a forced induction car I can't see why anyone would go NA unless you're doing long durations of WOT where heat is an issue. With a blower you can have street car manners with insane power numbers.

I say do a terminator drivetrain swap and if you have the coin upgrade the blower. You can be at 6-700rwhp depending upon what you want to spend with out even cracking the motor open.

I have never owned a forced induction myself. The reason I want to keep this car is because a family member passed it down to me and he has had the car since it was brand new in 1998. I would really like to hang onto the car, but the more and more I think about it, the more sense upgrading to an 03-04 cobra makes. I've put a lot of thought into what I want to do and I'm looking at it this way. Say I was to go the forced induction route with my current cobra. If I was to sell my current cobra and say I get a generous 7-8,000, would it be worth it to spend the 14-15,000 I'll need for a cobra? I feel like I could build a beast out of my 97 Cobra if I went with forced induction with that kind of money to dump into it. Thoughts? Feel free to tell me I'm an idiot

 

[cj428mach]

Im saying for the money do a terminator
drivetrain swap if you're attached to the car. A terminator motor with a ported stock blower will make your power goals and will drive like stock. The terminator setup will also allow you to grow in power up to 700+ rwhp and again will drive like stock out of boost.

 

[cj428mach]

Buying an 03 04 cobra will always make more sense financially than terminator drivetrain swapping a car. It probably makes more sense up front to just buy the 03-04 but it definitely makes more sense when you go to resell.
If you have an attachment to the car then keep it and add hp, but I think id add the terminator drivetrain over trying to build a 500hp na mod motor.

 

[Abneycody]

Buying an 03 04 cobra will always make more sense financially than terminator drivetrain swapping a car. It probably makes more sense up front to just buy the 03-04 but it definitely makes more sense when you go to resell.
If you have an attachment to the car then keep it and add hp, but I think id add the terminator drivetrain over trying to build a 500hp na mod motor.

What if I decided to go with forced induction on my car? Would the terminator still be a better option?

 

[Abneycody]

What if I decided to go with forced induction on my car? Would the terminator still be a better option?

And by drivetrain swap, you do mean throwing an 04 motor in my car correct?

 

[cj428mach]

You'll need to build the motor in order to make the 500rwhp with out it blowing up. Then you'll probably have to deal with issues with the transmission if you put a lot of power to it as well.

The Terminators were more than just a blower on a stock 4.6l cobra motor. The motors were built with forged internals, the transmissions were t56 6 speeds that can handle the extra power, and were upgraded to 31 spline IRS over the early cobra's 28 spline setup. With your car being an SRA car you may want to stay with that but what I'm getting at is the whole drivetrain was upgraded. The best solution is to find something like this

http://www.ebay.com/itm/COBRA-SVT-M...ash=item1ec2d90f49:g:rFkAAOSw9mFWL3y5&vxp=mtr

 

[nomoretickets]

The question I have to ask is what is the real goal here? Are you looking to do something fun and unique? If thats the case, I get it. Cars are a form of self expression. But if you just want to make 500 at the wheel and you are working with a $10k budget, you have ALOT of options going down the FI path. centri on 10 lbs of boost will get you mid 400's at the wheel on the stock drivetrain with full bolt ons. Or you could even go with a turbo setup. The problem with this is you wont really be able to safely hit 500 on the stock bottom end. mid to low 400's is going to be about as high as you can go safely on the stock bottom end.

another thing that hasnt really been brought up so far is the driveline issue. this is going to be a problem no matter what route you go down. Even if you have a built 5.3 fully forged, the t45 is going to be a weak link above 400 hp. Some people have great luck up to 600, some blow them out with bolt ons. So going to 500 wheel, the transmission is for sure your weak spot. And you gotta consider the rear end if you ever are going to launch the car.

My $0.02 is pick your FI setup of choice, make mid to low 400's. have a ton of fun. If its still not enough, forge the bottom end and up the boost.

 

[Abneycody]

The question I have to ask is what is the real goal here? Are you looking to do something fun and unique? If thats the case, I get it. Cars are a form of self expression. But if you just want to make 500 at the wheel and you are working with a $10k budget, you have ALOT of options going down the FI path. centri on 10 lbs of boost will get you mid 400's at the wheel on the stock drivetrain with full bolt ons. Or you could even go with a turbo setup. The problem with this is you wont really be able to safely hit 500 on the stock bottom end. mid to low 400's is going to be about as high as you can go safely on the stock bottom end.

another thing that hasnt really been brought up so far is the driveline issue. this is going to be a problem no matter what route you go down. Even if you have a built 5.3 fully forged, the t45 is going to be a weak link above 400 hp. Some people have great luck up to 600, some blow them out with bolt ons. So going to 500 wheel, the transmission is for sure your weak spot. And you gotta consider the rear end if you ever are going to launch the car.

My $0.02 is pick your FI setup of choice, make mid to low 400's. have a ton of fun. If its still not enough, forge the bottom end and up the boost.

My goal is 5-600hp. Just enough to have a bad ass Cobra, and also something to tear off in when some ricer in his v-tech pulls up thinking his ride is badass. As mentioned before, I originally wanted to stay n/a, but after doing more research and chatting with you knowledgeable advocates, forced induction is now something I'd be more than willing to do.

With that being said... In order to get the results I want, I'll need a s/c, forged internals, a stronger tranny, and a built rear end? I don't plan on taking it to the drag strip so I wouldn't be launching it very often... unless the vaping v-techer pulls up next to me. At that point, would it be more cost effective to A) buy a 03/04 terminator, B) engine/driveline swap a 03/04 terminator into my car or C) forge my internals, upgrade tranny, and s/c the 97. I know I'm probably beating a beaten dead horse, but appreciate the replies

 

[cbr repsol]

You could always do a coyote swap and boost that engine. They handle a lot more power than your stock motor would.

 

[Abneycody]

You could always do a coyote swap and boost that engine. They handle a lot more power than your stock motor would.

Wouldn't I still run into issues with putting power to the stock tranny?

 

[cbr repsol]

You would most likely be ok with a stock coyote.
They are like 435 hp and probably put anywhere from 350 to 370 rwhp
If you put a power adder on anything your gonna have to simply upgrade anyways. Find a nice used t56 with 26 spline input shaft and run a McCloud rxt clutch. Should be plenty fine with that.

 

[nomoretickets]

Idk which is really most cost effective. That's depends mostly on how much work you are willing to do yourself. The way termi prices are going, i'd say the $ per rwhp balance might weigh in favor of building your car rather than buying into a termi.

Of course, if the goal is just a fast car that can romp on 90% of other street cars, a mild boost b head car with basic suspension, gears, and DRs will run low 12's to 11's all day long. Maybe you won't have the bragging rights of making XXXrwhp but the car will be plenty fast. Personally, I wouldn't worry too much about the final horsepower numbers, and focus more on building the best car for the money. mild boost b head car will get you there in budget, and give you room to grow down the line as additional funds free up.

I further recommend that you check out the sticky on basic mods for sure. It covers bolt-ons and the basic suspension mods very well, all of which helps with with getting these cars to run quick times, regardless of HP output.

Edit: Just re-read this. Oh boy. Edited for clarity of advice and typos. dont drink and forum on your phone, kids