The body looks great , It looks like a great car to begin with, good luck on your project, keep us posted... The 451 is a good idea, "but" you could just build a decent 0.03" over bore 383 block w/3.75" stroke 440 crank turn down to between 7.125"-7.250" counter weight diameter & have the mains turned to the proper diameter also, so it will fit in a B-series block, you would get 432ci out of your 383 & be just as good (Shy 19ci though) as the 451ci/400 base B-engine & you will be able maintain the original 383 numbers matching block.... Check Mancini Racing or 440source.com for full piston, rod, crankshaft & ready to drop in kits