fabbing an intake manifold

I am having a hard time finding a late model intake manifold. Is there any reason I can't make a manifold out of exhaust tubing? I would make it with equal length curve runners a lot like the late model manifold, but I could build it to place the peak torque and hp wherever I want, which would help since my stroker is limited to 4600 rpms and the stock manifold is tuned to have peak torque at 4900rpms. I might even use two renix tb's instead of trying to use a mustang tb. Does anybody have any suggestions or comments on this idea?

Yeah!!!!!!!Your crazy!Unless youve got a "flow bench" and a whole lot of time!

Go for it there is no reason that u couldnt make one Exhust pipe will be a bit biger thena u would want for the runners though. Just do all the math and fab one up out of fiber glass that is if it won't die from teh heat of being over the exhust manafold. But when u have the intake out you could wrap the mamafold with header wrap to help keep the fiber glass from going up in smoke. I say Go for it.

Fenton Beech

P.S. I bought some nomex undies the other day so let me have it.

I have a spare from my 97 4.0. Sent you a PM

SeanP

The stock intake manifold is tuned to resonate at 4900rpm on a stock 4.0 but on a 4.6L stroker with a 9.5:1 CR, it resonates at 4600rpm. That's where you want it because that's about where maximum HP will appear.
The ideal intake manifold volume should be equal to the engine's displacement x volumetric efficiency %/100. Assuming a 90% VE for a well-built 4588cc stroker, that comes to 4130cc. The '99+ intake manifold has a volume of 4300cc so it's close to ideal for a 4.6L stroker, and perfectly ideal for a 4.7L stroker.
Take a look on e-bay and see if you can find one cheaply. I wanted one myself but I couldn't find one for less than $180 and I considered that too much, especially since I also need the later-style PS pump bracket and pump which add even more to the cost.
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Dino's "Mean Green Machine"
1992 XJ Laredo 4-dr - 4.6L I6 HO Stroker - 177k miles - AX15, NP231, D35c, D30

Estimated 263hp/323lbft, best 1/4 mile [email protected] before stroker install
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks

I have sold several late model manifolds on Ebay for $149 in the last few weeks. They are available - If you want to fab a manifold and your time and materials are free you might end up costing less - but I doubt it.