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Stock manifolds vs. headers

PostPosted: 07 Mar 2006 9:46
by jr

PostPosted: 07 Mar 2006 11:20
by dave-r
Interesting article. But this was a very mild engine.

There are much higher gains with headers as the performance of an engine is increased.
Eventually, given the right heads and cam, the Hooker Super Comps would have come out on top out of that selection.

Just as an illustration. A friend of mine fitted headers to his mild 440 and got a 25hp increase.

Another friend recently tried stock HP manifolds on his stroked 440 and lost about 80hp from his baseline figure. This was before the heads were ported so I think he would have lost even more.

PostPosted: 07 Mar 2006 15:31
by 1178
I went both routs with my stock 383. the headers took all of my low end torque away and only gave a minimul hp gain. the manifolds are much better on my application. the only diviation from stock on mine is a 30 over bore and a cam. just my two cents

PostPosted: 07 Mar 2006 16:34
by Jon
Good article. I didn't notice the effects of back pressure from a muffler equipped system mentioned though. One would think it would reduce the headers numbers the most(?).

How much would you think these vintage Hookers are losing due to the customizing? The exhaust scavaging on the cylinder connected to the flattened tubing must be compromised. Hate to get rid of them though they don't even leak yet!

Jon

PostPosted: 07 Mar 2006 17:27
by jr
Hey Jon, when did you took that photo of my Challenger? Because my Hedmans look just like that. :)

PostPosted: 07 Mar 2006 18:50
by Jon
Well jr. I am glad to see I'm not the only one driving that way. Do you have this modification also? :lol: That's about 1/2" of forged steel bellhousing there.

Sorry, a little off subject. :oops:

Jon

same test on a 440

PostPosted: 21 Mar 2006 14:25
by itsfred
i would like to see the same test performed on a 440.
then take a set of hp manifolds and clean them up maybe extrude hone them, port match generally a little tlc and see what you get.
(i know the honing is very expensive but was just curious)
just another thought also try a set of max wedge manifolds
fred