[Ekliptix]

Originally Posted by Mike C

Then why pay extra for the 3" exhaust? You pay for installation because it's more difficult to fit, you pay for material, pay for mufflers, etc. Not knowing your age or how much you may wind up driving it you probably regret that. WAY more expensive to boot.

Engine masters did a YouTube on a 2 1/2" vs 3" exhaust on a 650 hp 454. Even on that relatively high output built motor the gain was only 20 hp and that was at the highest rpm range. That test talked me out of 3" for my Camaro.

That test and video convinced me to go WITH 3". It dispelled the idea that more flow (3") reduces power and 2.5" would add 'needed' back pressure to improve power. There were gains through the entire RPM range with 3" over the 2.5". https://www.youtube.com/watch?v=_PVXvHkr-Vs. I admit my engine is not making as much power as theirs, but I do not believe I am losing any power with 3".

My setup is a 402BB making 430hp/460tq and I went with 3" for the potential power gains plus the bigger sound I'm hoping for. I even bought the CCP (CPP?) cross member to route the 3" exhaust through. However, in my case the Hooker headers came out too low, so the exhaust is running under both crossmembers now.

However, there was a clearance issue. The exhaust shop had me come in for them to explain. My truck is has a 6" lowering coil in the rear (ECE). Specifically they could not get the 3" exhaust over the axle and around the Super Track Bar easily. They said the only way was with a ton of exhaust cuts + welds that would cost a lot more. So, they did 3" all the way back into the mufflers (with an x-pipe) then 2.5" from the mufflers back. It's all done but I have not had time to head to my mechanic's place to hear it running.