I have a set of exhaust manifolds with the 3 inch y-pipe and cat from a 5.7 tpi car. Right now on the car I have the stock 5.0 tbi manifolds and y-pipe. I can definitely see the difference in size comparing the y-pipes to each other, but at a glance the exhaust manifolds look like they have the same size collector flanges. Is there a difference between the collector sizes on the two different manifolds or is just the y-pipe that's bigger in size???

 

I am pretty sure the L98 stuff is bigger all the way around. I know the ypipe is bigger and so are the primaries. I am not sure about the collector. Both may be 2". I will measure mine tomm.

 

Thanks for the response Shifty. I guess I could look at mine too, but I just barely put the y-pipe back in about a week ago and really don't want to drop it all over again just to compare collector sizes! I'm mainly interested in the difference so I can maybe get out of having to change the manifolds along with the y-pipe. Y-pipe changeover=15 minutes, changing manifolds=lots of swear words and who knows how much time. BTW I noticed you're in the Dayton area. You can give my old man a kick in the ***. He lives in Beavercreek.