What is the diameter of the exhaust inlet on a 1991 chevy c1500?

Question

I want to get a better sounding muffler than stock for my 1991 chevy 1500, but i dont know the size of the inlet, and of course buying the wrong size could cause problems for me, and id rather not waste money...thanks!

Answer 1

It depends on what engine is in it. If you have a 4.3L or 5.0L it is 2 1/4" if it's a 5.7L it's 2 1/2". This goes for all of the 1500's from '88-'92. In 1993 they changed all of them to 2 1/2".

I used to own an '88 GMC K1500 ex-cab 4x4 with an 8' bed (155" wheelbase) It only had the 305 in it (I didn't order it that way). I wanted to do the same as you, but there were no aftermarket cat back systems for the 305 trucks back then. I ended up removing the muffler completely and having a local muffler shop fab up a Y-pipe behind the cat and run 2 straight pipes right out the back, one on each side of the Reese hitch. Even with that 305 it was one of the best sounding exhaust systems I've ever owned.

Answer 2

2 and 3/4 inches to 3 inches!