Mike, I want to bring up a few points that I think are worth clarifying for some of us. I think we previously established here that the 69 A12's had a standard 1 bolt cam and the nylon tooth timing gear with street hemi (black) valve springs. The 70 and 71 cams had the roller timing chains and I don't know if they were 1 or 3 bolt cams? Now I don't remember seeing this disputed in previous threads regarding the A12 cam but the A12 cam was not advertised as the same spec as the 383/440 HP cars. The A12 cam was advertised as 276-292 54 overlap (look at the 1969 Plymouth tells it like it is Sixbbl ad). The service manual lists a 383/440 HP "Power Pack" B-Body cam as a 268 284 46 cam (with red colored valve springs) The 383 Cuda's had yet a slightly different specification than the "Power Pack". The six pack's 292 exhaust duration would definitely give the A12 more rpm's, more torque at higher rpm's and the springs would help prevent valve float. The hot aftermarket replacement wedge cam of the time was the "Hemi" grind which had a 284 284 specification and was typically available with 3 bolts. I believe this ultimately became Chrysler's standard "Purple" cam. The A12 did have the same ratio rockers but were a tighter fit on the rocker shaft (round hole vs oval) and supposed to be heavier duty... but the sixpack cam is different. My