most performance out of a muffler

[oldtimer]

I have a 1989 350 shortbed and right now I have a no cataltyic converter just a glasspack and tips going at a 45 degree angle. I want to put a cat on and a muffler with 90 degree tips. I was wondering what series of flowmaster would give me the most power and still sound good. what would be the best performance cat to put on.

Thank you

[J to the izA]

of the street series mufflers, i would think the delta flow 40 would have the highest flow rating