I went to put the dual cat Y-pipe in my IROC today and the passenger side head pipe just wouldn't fit. The car came with TPI, Auto, and a single cat. I thought it's supposed to fit in place of the single cat Y-pipe? Are there different TPI exhuast manifolds for single cat and dual cats? I bought the dual cat hanger, AIR tubes, and cat clamp from a local chevy dealer to make it all easier. I know it isn't supposed to fit the original intermediate pipe. I just want the Y-pipe to fit by itself. Any suggestions or comments?

 

yeah, there are different manifolds. a speed density TPI car like yours would have either one of two manifold designss: The G92 305/350 manifold, or the regular 305 TPI manifold, which is actually the TBI 305 manifold as well. In fact, your entire stock exhaust is the same as a TBI car. You will need the better manifolds for the y-pipe to work.

 

That explains it then. Time to track down a set of manifolds.

Thanks,
Larry

 

do you got the exhaust spacer that goes on the passenger side of the engine. this fits between the manifold and the y-pipe. this could be your problem if you dont have one.

 

Jermem, do you mean the donut that sits between the manifold and headpipe, or is it something different? I think JM is right, because the rest of the exhaust was the crappy 2.25" TBI system. If new manifolds aren't that much I'll just buy them from the dealership. If they're more than $100, I gotta find a decent used set. Oh the fun I'm gonna have after work this week.