ported exhaust manifold

[Rootie524]

ok..im not in the mood to drop $500+ into S&S headers so i was thinking about going to the junk yard and getting a spare set of exhaust manifolds and porting them. i got a buddy that does port/bore work. just wondering how to do this properly. i've heard its a delicate procedure because with some port work, if its not precise, it will do damage to the engine. i dont know if that holds true with the exhaust manifold or not.

[Superdave]

it's a complete waste of time on these manifolds. The poor design is the problem, and no porting can fix that.


Not sure what car you have but the 3500 LX9 manifolds are a huge upgrade from the old logs. Not quite as good as headers but way better than stock.

[Nick-G]

Honestly even a good port job on stock exhaust manifolds will give very minimal gains.

Edit: Missed the post above agreed 100%

[Rootie524]

i have a malibu with the 3100sfi v6.. so still it wont do much? but S&S headers would be good?

and im thinking about a highflow cat and running 2.5" mandrel bent pipes to my aero at2525 muffler. would i see gains from the highflow and .5" bigger pipes at least?

[Superdave]

S&S won't do much of anything because they are out of business... lol


2.5" is plenty for a 3100, make sure to take the downpipe flange off the rear manifold and cut out the funnel piece in there. Most people just cut everything off of the flange and weld a 2.5" pipe straight to it.

You will see some decent gains going that route.

[Rootie524]

it looks like andyautosport still stocks em though: http://www.andysautosport.com/chevro...d00176817.html

but thanks for the help. im gonna be jacking the car up tomorrow to see what kind of bends/pipes i need. going to try to do as little bends as possible.