Cranking Compression

There are two possibilities on the pistons so maybe I'm incorrect here... But this is taken from Summit's site:




Brand
Sealed PowerManufacturer's Part NumberZ405PPart TypePistonsProduct LineFederal Mogul Cast PistonsSummit Racing Part NumberSTL-405P Bore (in)4.000 in.Bore (mm)101.600mmPiston StyleDish, with four valve reliefsPiston MaterialCast aluminumCompression Distance (in)1.576 in.Wrist Pin StylePress-fitPin Diameter (in)0.984 in.Piston Ring Thickness5/64 in. x 5/64 in. x 3/16 in.QuantitySold individually.NotesRecessed piston head is 0.0705 inch deep x 3.140 inch diameter.

That being said... You dont have enough compression for that cam, even if it's 9.5:1. It should be 10.5:1 for those heads, even using the old "ad a point" rule for aluminum. Truthfully I would have liked to see 10.75:1 with those heads and a good quench for a cam like that.