I have a 1992 Camaro 350 with the dual cat/y pipe set up. It would be easier due to aftermarket part availability to go to a standard y pipe set up? How big would I need a standard y pipe to be to outflow my current, stock set up with the 2, 2 1/2" pipes? Or should I just try to have some one custom fabricate two 3" pipes into a 3" cat back?

 

Doug thorely and hooker both make a nice y-pipe setup. 2.5" y-pipe is all you need. Run that to a 3" or 3.5" collector and straight back. Single pipe is perfectly fine. Just remember the larger the diameter the larger the cost of cat, mufflers, resonators ect...

Just about any aftermarket Y-pipe will outflow your current.