I've head on a 400 based motor when you get to the 500" mark the pistons have very short compression height which can sacrifice durability.
The rb platform with the 10.72 deck hight is perfect for a 500" motor. And can't be much heavier
Not true.
You can get into a rather short piston height (1.12 offered as a shelf stock piston)if you want to, but 1.32 used in a 512 build is not short by any means, just in comparison to boat anchor stock type 440 pistons. Look at the deck height and compression height on a lot of BBC stroker combos for a comparison of what works. The other thing, and most important when building a lot of power, is the strength of the 400 block. Much better than a 440.
