This is power added related so please read on. My current combo runs great, 383 stroker with JE Pistons -16cc pistons, Dart 215cc/72cc heads, and P1SC blower with a 3.70 pulley. Problem is my engine is too big for the blower (doesnt' build more than 5lbs with that pulley). The motor is currently 8.7:1 compression. What I want to do this winter is upgrade to the D1SC blower and swap out my pistons. I'm having trouble deciding which piston I want to use. Obviously I'm going forged but can't decide on which piston will get me to a compression ration of 9.2 to 9.5. Any suggestions or experiences?

Doing some more research this weekend I'm looking at instead of swapping pistons to swap heads to a 215cc intake/64cc combustion to raise my CR.

Still looking for some experiences / feedback.

ttt

How much boost will you be running with the new blower? I'm assuming you will be making more boost, so why do you want to up the compression as well?

I'm not able to make ove 5PSI right now using a P1-SC and 3.70 dia pulley at 5k rpms. Speaking to Procharger they said my motor might breath too well for the P1SC to keep up. My plan is to go to a D1SC and 10-12 PSI of boost. Upping the CR to ~9.25:1 at the same time. That 5PSI and 8.7:1 CR isn't doing that much right now.

What I was trying to get at is to do one change at a time. I think you will notice a big gain with just the larger blower & more boost.

Have too agree with just change out the blower first. Those boost numbers are based on stock configs, blower just cant keep up, your engine config is far from stock......I'd vote for bigger blower, and play with pulley size to get the boost where you want it, the lower CR will let you tweak to a desired power level and give a bit more of a safety factor. The boost monster must be appeased, the lower CR will let you get your hands closer to his mouth without getting them bitten off