I have a flowmaster muffer that I bought used a few years ago(In my younger dumber days), I relized today that it has a 2 1'2 inlet and that the 3" exhuast is clamped at the end into the mufffler so i'm not getting as good of a flow as I could. Is there a way a muffler shop can cut the inlet out and weld 3" to the muffler? Also on the dirver side of the muffler were there is just one outlet it looks let there is a spot you can cut out and run another inlet, can you run two in and two out?

 

for the cost of having the shop do the "rebuild"...why not just buy a decent muffler??

you'll get better flow, possibly better sound and probably similar cost

as for the end of the muffler, they stamp one uniform piece and use it on multiple mufflers. that way they dont have to make a unique end plate for every muffler design