I would think you would want compression in the 9.5:1 range. Issue is piston to head clearance. Measure how deep the relief is in the head to get an idea of how thin a gasket you can use. Bolt it together and check piston to head clearance by removing rod cap at TDC and measuring how far up piston travels until it hits the head.

Then if that works out degree in cam and check piston to valve clearance.