I have the 451 in my 68 charger rt... It happens to be a block from 72. It's a stroked 400 with 440 crank and 440 rods and Ross pistons. Dropped some ported and polished 906 heads with hardened seats and three angle valve job from a 440 my old boss was getting rid of in lieu of aluminum heads. Final compression came in at 10.1 or 10.2:1 (can't remember off top of my head) it runs on 91 octane pump gas and absolutely screams! Torquey low deck sleeper that confuses people when they look under the hood. I love it! I have a 73 400 motor & 727 I'm contemplating dropping in my /6 valiant if I come across a cheap/reasonable 8.75 locally... You will never be disappointed with a 451 build, and if you source the parts yourself and not get a kit you can build it with some budget in mind. Just my .02
