I have an 85 Iroc. They do not sell a cat back system for my car, but I love flowmaster. They only sell it for 86 and up! I asked SUMMIT if it will fit and they said yes. So I ordered the system for an 86 to a 91, and I also ordered the stock hiflow converter for an 85. So basiclly the converter fits right up, but the connection on the pipe that goes to the converter does not fit because it does not have the same connection. the converter has a 4 bolt square flange and the pipe has 2 or 3 bolt connection!! I will most likely cut of the old flange from the old pipe and put it on the new system! Has anyone had this problem before? What are my other options?

 

'85 was kind of a bastard year. Very few companies make anything specifically for it.

You would have been better off getting a direct-fit cat for the '86 TPI application as well. You could modify the y-pipe to fit the cat, and then the cat and cat-back would bolt together.

You best bet would probably be to return the cat and get the one that bolts to your cat-back.

 

But it would be the same issue, just with the cat and not the exhaust pipe! It's easier to do it to the pipe for me because its out of the car. The only time that Y pipe is coming out is when the engine swap happens!

 

The old pipe is on the left!

 

Cat back doesn't look like the right thing. Should be 3", that looks like 2-1/4".

 

it goes from 2.5 to 3 inch