Not having the "A" pool of knwledege, to draw upon,(this forum), I purchased a pre magnum, roller cam 318, complete engine. This to power my 67' cuda coupe. Plans have change since then and this build is to propell a 2,400 lb., Jensen Healy roadster. I have magnum "eddy's" and performer rpm, dual plane, of which I believe will tend to limit power over 6k rpm. ? Steel crank and .02" "hyper" pistons, shot peened magnum rods with ARP. bolts. I'm thinkin this should hold more rpm. ? Edelbrock says this is "only" manifold for Magnum heads. Thoughts ? Thanks, ateam.:cheers: