how much torque will I loose with a 3" true dual setup vs a 2.5" true dual setup on a 325 hp motor. the reason im asking is i just put in the 307 and the car needs exhaust but later on this year probably like november im throwin in my other sbc that im building. It should have about 475-500hp and the 3" will work good for that. but for now I need to get it done and I only wanna do it once. what do you guys think??

 

Do it once and be done with it.

 

Dual 2.5 is plenty, go 3 inch if you want the hassle of less clearance but a louder ride, the only people i ever see with dual 3 is mustangs who just came across a 3 inch offroad h pipe, the 2.5 will tuck everywhere easier.

 

Headers, yes?

Torque is more of a function of the primary tubing size than the size of the downstream exhaust.

 

i noticed an all round gain with the flow tech shorty i used a while back on a old car of mine..i didnt feel any loss down low, but the big end felt allot more in charge.