It's a crossbolted Megablock.

The T56 I've purchased is rated at 750ft lbs, which admittedly, is marginal.

8.5:1 is gonna have the slugs pretty far down in the hole. Doing the math on .060 deep and .045 gasket gets me around 9.5-9.7:1 with a 24cc dish piston. Is this OK?? S/F.....Ken M