If you're looking for 650 hp on your 512, I think you need more cam. My 400/512 according to a mobile chassis dyno produces 645 rwhp. My 512 has Stage 6 heads that flow 350@650 a solid roller that's 272@50 with 650 lift. I run a Super Victor intake with 950 QF carb on pumpgas with 10.5 cr. Makes my e body run 10.5s @125mph.