Im going to order new Magnaflow spun cats and need to know if the in/out is 2.25" or 2.5". Also should i get the offset ones or straight ones?

 

Stock manifolds and y pipe. What I want to know is if i can just replace stock cats with small universal cats in the y and maybe add a small filler section. Or do i have to have a new y put in. The drivers side cat is welded right to the manifold flange like every other 96 - 97 f body. And theres a bend right after the cat. So can i fit a small 8" long cat in the stock y pipe and do i need it offset on the exit side of the drivers side cat? I would think this would be a common situation. Anyone whos done this please let me know.

 

Well... I went to FI (97 - 383 - D1 M6) with dual cat Random Y pipe. It flows good. But, recently blew out the right side cat. Both cats were positioned under the passenger seat side. They performed well. They could not withstand the pressure/ flow loading of the Procharger D1. B.