500 vs 512 from 400ci

I have always used a Aftermarket Block @ 750+ HP.
I use 230 cold weather blooks on our Stocker but it is
475 to 500 HP.
I remember talking to someone at Koffels 3 or 4 years ago. They advised me to get the 230 heavy casting block and claimed they made 900hp engines using those.
I wanted to either use cross bolted main caps or BCR griddle with aluminum caps.
I will probably also half fill it as I did my current 530 casting block.