Compression is 9.6:1 OEM. The short block is loaded with a forged crank, balancing shafts, and I am not sure but the rods maybe too. This is an all-aluminum block with a lower girdle and cast-iron sleeves. I know for a fact that Karl's S/C tC was running 14.5PSI with the same NST pulley I am installing. He also was testing RippMods cams for them He switched back to the 12PSI pulley and they dyno'd at 325WHP I believe. That was with a stock short-block.
