I ordered some mufflers from my local parts store, and I got 2-1/4 in/out, is this correct or do I need the 2-1/2?

 

I think its 2- 1/4

 

I am curious as to why you do not simply measure the tail pipe on your car, so as to resolve this profound dilemma?

 

I thought the tailpipe was a larger diameter.

 

+1 on this... It is bigger...

 

If you measured them, and it's the stock pipe, you would have found it to be 2-1/4" outside diameter (OD). Both the stock mid and tail pipes are 2-1/4".

If you don't have a caliper then just wrap a string around the pipe and make a mark across the string where the ends crossover. Measure the distance between the marks, the is the pipes circumference--divide that by pi (3.1416) and the result, rounded to the nearest 1/4", is the diameter.

Exhaust pipe is sold by the outside diameter, in 1/4" increments; mufflers and such are designated by the size of the pipe they fit on to--so, if you have the stock tail pipe you got the correct mufflers...