'97 k2500 exhaust questions

[mcrisby]

Hey all, im planning on doing a overhaul to the exhaust on my truck when i get home for a few weeks, my truck as i mentioned is a '97 k2500 with the 5.7 in it. The stock exhaust system from the manifolds consist of two pipes and two cats running into a dual inlet muffler running out into a single outlet tailpipe. I plan on just cutting the stock muffler out and replacing it with a dual in - dual out magnaflow muffler with dual pipes out to the rear bumper... First off im not quite sure what diameter pipe runs into the muffler inlet... would anyone be able to tell me off hand what it should be? Really all i want to do is some exhaust work from the axle back...

Thanks!
Mark

[Meaderacer9]

diameter is 2.5in.