I have an 01 1500 4x4 with the 5.9 in it buying a muffler in an hour and need to know the in and out size I think it's 2.5 for both just wanna make sure!! Also how long is the stock muffler?

 

I would take a tape measure out and crawl under it. I think 2 1/2" sounds right, but not sure....

 

going to the cat i think is 2 and out of the cat is 2 1/2, the muffler should be 2 1/2 in and out

 

^ right

 

I've bought two 2.5" inlet/outlet mufflers for my 318 although a good welder would tell you it really does not matter as they are pretty good at going up and down sizes if they need to, if it's smooth flow you are after I'm pretty sure the 318's and 360's of the era used 2.5" pipes and I measured mine before it went under the knife.

 

It is 2 1/2 ...but what you need to know is if its inner diameter or outter...i believe its outter...

I bought a regular cherry bomb turbo muffler and its shorter than our exhaust...so if you get something like that you'll need about another 6inchesone of pipe in order to make it fill the gap of the old muffler

 

It is different for the last couple of years of 2nd Gen Rams.

This thread, located in the FAQ section, should answer any exhaust size questions.
https://dodgeforum.com/forum/2nd-gen...ram-1500s.html

 

On my 98 5.9 the muffler was 2.5" on both ends and then the tail pipe expanded to 3" past the muffler. The muffler is 34" long. These numbers are exact measurements and not guesses because I just pulled the stock exhaust off. It seems there are probably variations in exhaust systems.

 

Exhaust pipe is measured by inside diameter.

There is a diagram with pipe sizes in the faq section.