Looking to upgrade the exhaust manifolds for my stock 1999 502MPI with Corsa switchable exhaust. Anyone have any used Stainless Marine or CMI's with throttle/module/oil fliler brackets laying around that they want to unload ? Been watching ebay and classifieds and most have the long tailpipes. I need the stock manifold configuration.

I have a pair of stock CMI tailpipes for sale cheap, $350.00, all you have to buy is a set of CMI headers from Trick Marine!!

I have a set of CMI'S that i only used about 6 hrs. $2500.$4800 new with tailpipes and polished dist. lines.

scararb(or anyone who may know),
will you have a fuel mixture issue if you just add headers like CMIs?? or will the computer make up for it by itself??
what kind of gains would you see with just exhaust change, ive heard not much? any input??
kevin

I've been told That I will see absolutely no gains at all if you add exhaust to the 502 EFI . That's why I haven't done it . To see gains you will have to do some internal modifications to take advantage of the headers .

True, with this type of engine application, etc, you most likely will not see any performance gains on the top end, but you might see a little more midrange torque, but even then it is truely hard to say.

Some other bennefits to adding an aftermarket exhaust is that they weigh much less than the stock Merc cast iron manifolds, they have a much better appearance, and really dress up the engine(s), and they have a much nicer rumble/sound to them than the stock exhausts. Of course these additional bennefits I have just mentioned are all personal preference kind of stuff that may or may not matter much to you.