Swap out the rods with the scat small journal I beam rods.
Properly prepared vortec heads would work well or there are plenty of
aftermarket choices. Runner and chamber volume are critical. Intake runner
volume in the 170 - 180 cc range. Set up the piston to head clearance near
0.040", use combustion chamber volume to achieve the desired compression
Camshaft selection will depend on the intended RPM range.