An interesting episode for sure. Especially how little power loss there was with how long of pipe they had.
If you're ever wondering what exhaust to run on your setup. Consult this chart.
View attachment 1714936830
For the full maths, go here:
http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
It explains it all. But in short. A certain amount of horsepower flows a certain CFM. And a certain CFM requires a certain pipe size. Not really as complicated as it seems. I am going 3 inch on my setup. It's a lot. My 340 is really only going to put out 420ish horsepower. But I will be running nitrous. And with that I can definitely hit close to 600. Not to mention I will be doing head and cam work this winter and should end up in the 475 area N/A. 2-3/4 pipe being difficult to find I went 3 inch. Am I worried about torque loss down low? Not really. I'm going with an H pipe setup which should help balance things out. Going from manifolds and 2-1/4 to full length headers and 3 inch exhaust should make a serious improvement in my power. I'm curious to see what it does.