exhaust pipe diameter for a mildly modified 340

ir3333 said
I have read 2 1/4" diameter will support 400 hp. Any idea on how much power might be lost going to 2" diameter duals.
2 inch will be much lighter, leave more room and allow the use of quieter mufflers!

A 2-1/4 pipe size should be able to support 400hp. The problem is the muffler is cutting power.

My question to you is, how much HP does your engine make?
How quite do you want your exhaust?