That's a bit high for 03, 4 thread heads. I've seen them go for $400 plus shipping.
Consider too that they will need a valve job which will add another $300-$400. That would give you a set of unported heads for $1k, once again, kinda pricey.
01 cobra heads -vs- 03 Mach 1 heads
- Thread starter Lumpydogs
- Start date
That's a bit high for 03, 4 thread heads. I've seen them go for $400 plus shipping.
Consider too that they will need a valve job which will add another $300-$400. That would give you a set of unported heads for $1k, once again, kinda pricey.
Everything bolts up perfectly (front cover, intake manifold, cam covers) except for the exhaust manifolds. The later 03/04 heads have a different exhaust port than the 99/01 heads. You can either get a set of used 03 cobra/mach exhaust manifolds, or a set of new shorty headers for the 03 heads which will bolt up to your existing exhaust H or X pipe with no other modifications.
I have an aviator longblock that has the same heads that are on the mach/cobra/marauder. The only thing I needed to change was the exhaust and the flywheel. I got a set of 03 cobra manifolds for $20, and a fidanza aluminum flywheel. I would have put headers on it, but I couldn't affort it at the time. That's why I pulled an aviator motor from the junkyard in the first place.
But I have noticed that the 03 heads have MUCH more bottom end torque than my 99 heads, even with my original intake bolted up to them. However, the redline is about 500 rpms lower.
Homer
I have an aviator longblock that has the same heads that are on the mach/cobra/marauder. The only thing I needed to change was the exhaust and the flywheel. I got a set of 03 cobra manifolds for $20, and a fidanza aluminum flywheel. I would have put headers on it, but I couldn't affort it at the time. That's why I pulled an aviator motor from the junkyard in the first place.
But I have noticed that the 03 heads have MUCH more bottom end torque than my 99 heads, even with my original intake bolted up to them. However, the redline is about 500 rpms lower.
Homer
I've used 96-98 manifolds on 03/04 heads and their ports were more than large enough.
What do you mean by "the redline is about 500 rpms lower?" Do you mean make peak power 500rpm lower? The redline is a mechanical limit imposed by the ability of the internals. The 03/04 heads will make more power throught the entire RPM range and will not affect the "redline" one bit. If you are using the 03/04 cams the there will be more torque and the power will peak at a lower rpm.
It was the cheapest I found at the time.:shrug:
vids... part1 http://www.youtube.com/user/BlkSVTCobra01#p/a/u/1/EfI7nqJ8Mlc part2 http://www.youtube.com/user/BlkSVTCobra01#p/a/u/2/sCWNGGQ9ws0
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Those 99-01 cobra cams do even out the better head flow design of the newedge Mach1's!
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are there any ptv modifications needed to bolt on a set of 03/04 heads on a 99 shortblock with a set of fr500 cams?
No PTV issues with a stock shortblock and FR500 cams. The FR500 cam kits are no longer available...but I have one kit left if you're interested in getting one.
I don't understand what you mean.
Here is the Dyno difference between the '01 heads and the '03 Mach 1 heads.
Same car, same dyno, same tune. Only changes are the cylinder heads and a Melling Billet Oil Pump. I can't imagine the oil pump making any real difference.
Note, the 2008 run is with the '01 heads and the 2009 run is with the '03 Mach 1 heads.
Same car, same dyno, same tune. Only changes are the cylinder heads and a Melling Billet Oil Pump. I can't imagine the oil pump making any real difference.
Note, the 2008 run is with the '01 heads and the 2009 run is with the '03 Mach 1 heads.
interesting...I wonder if the margin would differ much under FI
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Same cams? What about the exhaust manifolds?
Interesting dyno graph. Thanks for sharing!
Homer
Interesting dyno graph. Thanks for sharing!
Homer
The margin will increase with FI. The more power you make the wider that margin becomes. At 14.7 psi that margin should be nearly doubled.
good info thanks. I wish I could of done some actual tests. I swapped to the 03/04 heads/cams when I did my build.
Yes, the same cams and manifolds were used for both Dyno runs.
The cams are GT supercar cams and the exhaust manifolds are Ford Racing Shorties with Magnaflow catted x-pipe with Magnaflow mufflers.
The stock 99/01 or 96-98 cams probably would have made more power.
It does look like the 03/04 heads outperformed the 99/01 heads when just looking at the dyno graph, but there are a lot of variables in the heads that could result in mroe or less power. Those are combustion chamber size, valve sealing, and lash adjuster preload. A good valve job alone can increase over totally stock heads. Were the 99/01 heads fresh? Were the 03/04 heads milled? Then there are the dynos, they were done a year apart. The tune itself could have had more or less timing, a/f could have been more lean or rich, etc.
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I am making no claims about which heads are better, I'm only posting my results. The 01 heads were stock with about 25k miles on them. The 03 heads had a minor clean up (mill). The tune had the same timing and the same moderately rich A/F of 12 - 12.5 thru 6500 rpms then 11.5 above 6500. The block is a 4.6L stock block bored 0.020" over with a stroker kit.
p.s. I didn't switch to 03 heads for the increased power but as a cost effective replacement to my 01 heads that got trashed when my oil pump died on track and f'd up my 01 heads.
Thanks for sharing:rockon:
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