Bought new last year end of season Less than 50 laps moved to a different class. Stainless valves PAC beehive springs titanium retainers. These heads work Amazing identical to a GM Head. Undercover port work with GM part numbers 1.94 int 1.6 exh Flow number with the papers from Brzezinski. 2100 obo these heads are bolt on ready to go with a .480 lift hyd flat cam spring will take up to 600 lift.