Dual out muffler, or single out
 

I have a 1999 Blazer and recently dropped a vortec 350 in it to replace the worn out 4.3. I'm at the stage where I have to get an exhaust made up for it but I'm not sure what I want to go with. I already have the shorty headers that come with the swap kit and I know I want to run 3" pipe where ever I can. The only thing I keep wondering is if going from a 3" single into the muffler to a dual 2.5" tail pipes will gain me any power over just running a 3" single in and single out muffler. I plan on running a Flowmaster Super 40 muffler. I would like to run the single out just for space reasons so it goes out the stock or close to stock location, that and I'm not crazy about the dual tips out the back look for the blazers. Yet if there actually is some performance difference by having the dual tailpipes over the single I might go that route. Anyone have some possible incite.

Pure performance, and single 3" will actually flow more than two 2.5s It has more velocity. Only downside is you still have single exhaust.