I have a fresh 468 that needs a cam. Specs: '70 455 +.030" and 4.250 Butler assembly, #64 heads compression set at 9.3, head ports cleaned up, stock intake, Q-Jet, pertronix in stock distributor, Ram Air manifolds with Pypes 2.5" system. Will be in a '70 GTO convertible, M-21 with 3.31 12 bolt saf-t-track. I have installed 2 Summit 2802 cams and both have failed break-in

. 1 lifter would not spin on first cam, 4 would not spin on second. Did all the proper procedures. Looking to get away from the Summit line even though I never had a problem in the past. I do NOT want/need to go roller. Want a strong runner nothing wild. Thanks for positive comments.