On a stock LT1 w/M6, I've been thinking about the Magnaflow 3" catback. My question is, is most of the gain in the muffler or the pipe or both? In other words, if I just go with a Magnaflow muffler instead of replacing my stock pipes, will I still get any hp gain?

 

Most catback make around 10 RWHP.

 

i would jsut goahead and ge thte catback. you can find a used catback on here for abotu the price of a new muffler(installed). I went with a hooker catback and love it. Sounds good and the buttdyno says i picked up a few ponies. go ahead and get the catback so you dont have to backtrack later on as you get a cam, headers, etc. Now if you are not going to be doing any mods and jsut want something that sounds nice just get the muffler.

 

the hp gain comes from a combo of the larger diameter pipe and the better flowing muffler. I would just go ahead and get the whole catback, like said above you can find some nice deals in the for sale section.

 

I'd say it's probably mostly in the pipes. Regardless, get both.