I have a 454 bored .60 so I am thinking she's now 496. I'm really only concerned with big torque for 0-60/70 times. Planning on this going into my 72 SS Clone backed up with a M21. I have a pair of heads from 71 402 Chevelle. Casting 3999241. These any good or am I better off with a set of decent aluminum heads. Pretty much looking for a stop light runner with nice highway speed. My 72 has a 3:55 axle I'd like to keep in her... Also have a 77 Z28 I plan on using 1 71 Vette CJL 4-speed 350 in. I have a pair of 68-69 Camaro factory heads 3947041. Got flat tops in it, hope these heads provide a decent CR not too high and I want to keep my A/C in her.