I have dual cats on my car. I wanna keep it dual, but I all already gotten a 3 inch system before and after the cat. So, my question is which cat thats 3inches can I fit in there?
Thanx,
PsychoGTA:lala:

 

You've got me confused. Do you mean you have a 3" cat-back that hooked up to the dual cats, and now have a y-pipe that has a 3" connection at the cat? And you're wondering how to connect the two with a 3" cat?

If so, the only way would be to modify the cat-back connection to the cat. For that, you could use a universal 3" cat and have a pipe inserted after the cat to connect to the cat-back where it is one pipe (cut off the y), or get a direct-fit cat for '86-'90 TPI applications, and have the cat-back modified to connect to it.

Another possibility to consider is cut off the 3" portion of the y-pipe and extend the individual tubes to the individual cats. That would be my choice if I already had dual cats, but it's not my car.

 

I got brand new headers. From the headers to the dual cat, im gonna be running 3 inch pipes. Because I already got the 3inch cut-out. I dont have no y-pipe, thats y i'm want to get 2 3inch cats. Then after the cat i'm gonna have a 3inch y-collector.The exhaust I got is a 3 inch inlet and 2.5 inch outlet. So do u think I can fit 2 3inch cats under there? Hope this makes better sense.
Thanx,
PsychoGTA:lala:

 

Probably. The inlet/outlet size doesn't usually relate to the body size.

What kind of headers? 2-1/2" from each side to 2-1/2" dual cats y'd to 3" cat-back would support most any SBC.

 

heres a pic of the dual cat setup if youd like to see it.....