4.350 x 3.764, 9.7 compression, 1971 820 GM oval port heads, Comp cams roller tip rockers, .080 wall chromoly pushrods, factory 390 HP cast iron intake with a Q-Jet. The centerpiece of my build a 350 HP 396 factory hydraulic cam 214/218/460/480/112 with 1970s TRW hyd lifters. Some pictures.