The CNC chambers measure 74cc. The intake valve is 2.200-inches and the exhaust valve is a 1.700-inch. Valve lengths are 6.200-inch and the valve angle is 14 degrees allowing them to work with stock pistons if desired. The minimum bore size is 4.150-inch. These heads bolt to standard Pontiac blocks with no problem and they do not require offset lifters. Complete heads come with 1200 series Ferrea valves (better then 6000 series), titanium retainers, 10 degree locks, PC seals, PAC roller cam springs for .750 lift, ARP rocker studs, spring cups and a 5 angle valve job.