Diameter of stock exhaust?

[Diesel]

Cummins or nothing! (unlessssss its one of the square nose dutys that look like a modern first gen with the 6.7)

[ArtBee]

My 93 D350 is 3" stock. I had a straight pipe 53" long expanded on each end, cut out the original muffler and welded in the straight pipe. Fit perfectly, didn't take long to do and the truck sounds great ... even picked up some power and fuel mileage.

[Diesel]

So you cut out the muffler and that little bend down before the muffler and replaced it with the 53" pipe?