Bassani Y pipe. I got mine used for a couple hundred bucks. Or find a shop that will actually remove cats. most wont.

I have a universal cat behind my y pipe and then a 40 series flowmaster. I could tell very little difference between how it sounded with and without the cat on it. It's mildly loud.

It is probably a good idea to replace your cats at this point anyway, that is a high mileage truck right?