Whats the best cylinder. Head choice for a stock 440 block full race motor 511 ci. That hopefully won't break block

On your deal using a stock 440 block, even with aluminum main caps and studs, your best bet is to shoot for under 700 HP at WOT best RPM
I've seen 4 stock 440 blocks with stock main caps and several with aftermarket main caps crack the main webbing making above 750 HP on race gas
If I was you I would sell that 440 block and look for a good 400 block to build

Trick Flow 270 head with a Indy 4500 intake. With good compression and the right cam you should have about 750 hp which is about as much as you want to make with a stock block.

Full race I would go with the 440 CNC -1's

I run a stock 400 block tall filled with billet main caps. At 502 cid makes 850.....

My current 505 C.I. E85 bracket motor with CNC 440-1 heads and Jesel 1.55 ratio rockers and a 400-3 intake with 15.2t o1 compression ratio makes between 850 and 905 HP depending which online calculator I use based on ET or MPH in the 1/8 mile in my soon to be sold 1970 Cuda S/P car that weighs right at 2850 Lbs. with me in it