[mattpatt]

It's been a while and I came across this thread. Just some more info for folks. I have SPF #3033. It came with 2" mufflers (as near as I can tell by measuring the ID of the mufflers). The engine is a KC 427W (just a basic induction - 780 Quick Fuel, Air Gap manifold). Attached (I hope I did the attachment right) are the fly wheel HP/Torque curves at KC compared to the rear wheel measurements (inertial dyno in 4th gear). The torque lose across the band is about constant and doesn't show much evidence of "choking" from the exhaust (i.e., more loss as the rpm increases). The total loss across the band is about 26%. Assuming around 20 hp peak hp loss the rest of the losses account for about 20%. I would have expected more like 15% so maybe the pipes have a bit more loss (or maybe the dynos account for difference)? Anyway, it's plenty of power for me with a reasonably flat torque curve and I'm sure my neighbors wouldn't appreciate the car being louder than it already is (I set off 6 car alarms coming home from breakfast last week).

Matt