exhaust manifold gasket matching

[85erbirdie]

heres one for the sience to gasket match or not to gasket match exhaust manifolds i understand about the pulse waves and suction pulses during blowdown while in overlap but i here to many different opions about matching that leaving a lip between the head or manifold or gasket helps to avoid reversion but i thought that was more criticall on the intake side

[bob442]

you have valid points, but with headers theres less worry with reversion, with stock logs, its a worry. Ben says to not gasket match the exhaust ports, just clean them up. also you reduce back pressure where its needed. The only time you dont want back pressure is if you have a blown alcohol 1500hsp motor. And even then guys running monster trucks say they pick up some bottom end with resinators off the straight headers used to reduce noise for arena shows. Basically clena up the ports so theres no place for carbon to stick to and build up.

[bszopi]

If you do any gasket matching, it should only be on the head. Even the stock log manifold openings are bigger than the gaskets, so you will still retain the lip. But, I agree with about to what Ben said - to not gasket match the exhaust ports, just clean them up.

[85erbirdie]

ive always been tought and makes sence from a "think like a lazy air molicule" view but cleaning the casting bumbs and sharp edges out so when doing that in the stock exhaust man this does effect were the reversion accours at just like changing primary tube and length on headers yes?? sometimes it just takes a while for my brain to catch up add and all that crap ok being out here in crappy california it tends to be difficult at times to get away with under hood mods that are visual so for me to try to modify the monifolds by either extrude honing porting or even manipulating colecter size would be worth the time plus the cops out here make you pop the hood and write tickets then you get to bring ur carb certs on the parts to court so out of sight out of mind is the best plus it works good at the races to lol

[Superdave]

Do they make RWD 60v6 headers that meet California specs?



Porting manifolds is typically a huge waste of time, Headers will always be the better option.

[85erbirdie]

found some on ebay not sure if their carb approved or not and ya i do realize manifolds will not perform like headers but im also not running 1/4 mile not ready but i can cause a little rucus on the street ive allready gone threw everything from the throttle body to the exhaust manifolds plus had the heads milled .025 nice valve cut and 1.6 roller tip comp rockers but know i have to change the water pump timing cover and oil pan im sure you know why motor swap long sorry but just another present the ex-wife left for me to fix and i have been watching this forum for while before i signed up and ive seen your work in here very impressive inovative maybe we can trade notes some time i grew up around mopars but when i got this bird like 6 yrs ago i was very impressed of the small displacement and the performance it gave id really like to put a turbo on it with a water injection to really make it come alive