Pontiac X4 block(73) 6X-8 Heads, Comp Cam X#262H, HEI This is a REGULAR GAS engine--appx 8.2 compression engine. Prof rebuild and recently dyno-tuned at a prominent race engine shop. On 2nd pull showed 337 HP and 430 lbs of torque.. sweet running engine-fully broken in, ready to install. Full details upon request including videos of dyno test.