[Coloradocobra]

Thanks for posting your curve. Mine is similar but even more dramatic. The HP curve climbs to 4000 but then is absolutely flat, so you can imagine what the torque does. The Midstates sidepipes are a 2.5 inch inlet inside a 3.5 inch pipe and you may be right about restriction. I have run open "shorties" (I welded in a 3 bolt flange on each side for a quick-change) and to be honest, it did not seem, by seat of the pants, to help much. I hope to run the engine on a dyno while it is out if I can scrape up the funds and will test it open and with mufflers. I plan to install new mufflers this year since I am going to get the headers and side pipes coated.

I am hesitant to change carb or manifold due to cost and also manifold vacuum looked good on the dyno indicating that any restriction does not seem to be on the intake side.

Gary