Sorry guys, but its hog-wash on it needing a 4 bolt or girdle, studed so-forth for a 10sec. A body, i ran high 10s with a nothing 451, Dartsport ran high 9s with his 451, the combo looks fine, but i don't see it going high 10s, or even low 11s, umless you get the car down to 2500 with you in it.
The 2255s will be fine (but there heavy), this won't help, all though the .509 is a cool cam, i think you'll want something better like an XE or a smaller solid, & it all depends on the weight of the car with you in it, i'd shoot for 3-3100 race weight, its not to do in an A body, but no heavier then 3200, this is what i had in a 75 Duster, & at the end, it pulled off a 10.87 @ 123.58 running lean & a crappy 1.62 60ft.
75 Duster, all steel & glass, just fiberglass bumpers & homemade brackets, 3090 race weight. My boney azz only weighs 150 lbs.
400 low deck- 451
Ross FTs, 9.73.1 with 91cc 906s
Steel crank, stock rods, ARP wave-lok bolts
7 qt. pan
Un-ported 906 heads, just a good VJ with stainless 208/174 valves (back-cut)
Comp. XE 284H hyd., installed at 105.5
1.5 Ductile iron rockers
M1 Single, swapmeet 750dp
MSD Dig. 6
1.7/8 FW headers, 4400 PTC conv., 4.11 spooled 8.3/4
No lie, it ran a best of 10.91 @ 120.56 on a 1.51 in the best air. shifting at 5600
After i pulled the heads, spent a load of time porting them myself, they flow'd 265 & 198 at .550 lift
Installed a Solid 543/529 250/256 @ 50 Comp. on a 108, installed at 104
Installed a Weiand TR with 2 600 holleys & alittle tuneing, the 1st. pass in the dead summer heat & crappy traction, it pulled of a 10.87 @ 123.58 on a 1.62 60ft. shifting at 5700
So its not hard to pull off 11.0s, high 10s, its all in the combo.
I had 250 passes on this engine, never an issue, a guy i raced with ran high 10s NA with his old school 440, & 10.2-10.3 on the juice (100 shot), he had a good 300 passes on his, & he didn't believe in 1/8 mile, all 1/4 for him.
Now its been proven that the lowdeck 451 runs alittle stronger then the 440 in the same combo with everything being equal, but if you don't mind running race gas, or its primarly going to be a race car, i would work on the bowls, radious the short turn, bring back the pushrod pinch about .100" & back-cut the valves, drop in a .590 MP solid, dome 12.5.1 slugs, 850dp, 4500 9.5 conv. (a good one), i'm sure you'll be in the 10s with a good tune.