How crucial is it that the exhaust ports are matched? I am lookin to do a turbo set up, and i don't wanna spend top dollar for a set of headers i'm going to chop up. I can get a pair of SBC headers for 99 bucks but they have a round hole in the flange as opposed to the D port that is on the engine. Does it really matter?

 

i was wondering this as well ..

 

Find a set of damaged/unuseable headers and chop the flanges off and weld them to the set you want.

 

I would think there would be some sealing issues due to the mismatched ports possibly even leading to exhaust leaks.

 

they will most likely leak. the previous owner of my car installed sbc hooker super comp shorties and no matter what i did i could not get them to seal properly

 

Are you sure they will fit your car? If you dont know then I'd say they probibly wont... there is not much space between the fender walls and the headers on 4th gens. But on the same token... if they dont fit what the heck buy them anyways... sounds like a deal where you can make your money back on eBay. Just make sure you have a lead on a proper fitting header before you start the project otherwise you will waste a lot of time. I say buy them and let us know how it works out. As far as HP is concerned im not sure but IMO they will create turbulance right as the exuast exits the heads. Will it help scavanging? Probibly not if the aftermarket isnt doing it... and they throw tons of money at designing proper headers. Will they be better then stock though... hell yeah, but probibly not as good as d-ports. Its up to you if you think $9X.00 is worth a 14 hour job installing headers on a lt1 or spend some extra cash on d ports. Either or will net you good HP.

EDIT: just saw you were going for a turbo set up... probibly should move this thread to forced induction.

 

I don't think it would matter as a few headers are not D-port headers, like RK Sport...

 

I have a set of Hooker LT's and they are not D shaped!

 

As long as the opening into the header flange is larger than the port and there is enough surface to get a gasket seal it should work fine.

Rich

 

The headers I used on my LT1 swap are not D port shapped, because with the swap I can not use LT1 headers. Mine are for a L98 car. They do not leak one bit and I am running the Fel-pro gaskets on it.