Didn't you have the BOSS iron block? If so, that's a big bore (3.7") bore.its a t-56 6 speed
8.8 to 1 compression
4.6l based motor
custom cams
stroked
93 octane on the street tune and c16 116 octane on the race tune 25psi
im in the process of building a 283ci motor with stock heads, custom cams, t56 with the same turbo setup. 9.6 to 1 compression. should net similar results.