I'm a big fan of the 451, was building them years before they were 'flavor of the month'

I'm a little different in that I prefer the the shorter 6.36" 383 rods when using OEM because (if for no other reason) a beam with a shorter center to center and the same cross section and material is just a little stronger and the shorter rod 451 motors (to me) are just a little more responsive all else being equal.

Perfromer RPM or Holley SD, tweaked 906's and a good Hydraulic performance cam like the Lunati 235/245 @.050 or the Crower 231/240 @.050 along with a flat top 10:1 piston and a 750-800DP (with iron heads, go a bit larger with aftermarket Eddies/stealths) should run very well for you. Don't over think it because a 451 is really no more than a 'dimensionally optimized 440'; so any sound proven combo for a 440 works equally as well, if not just a hair better (lower overall bobweight and total installed weight) in a low deck 451.

With a 4 speed and 3.91's I might step up the cam to the Comp XE 241/247 but in a 108 intead of 106 and only if you're running aftermarket rockers, but I wouldn't run that cam with the oem stramped steel rockers.