Small Block Chevy for S/G

[Hypertoys]

Chip ,I am going with the 421 SBC for next year .I am using the Dart little M block ,Scat crank and rods,custom Bullet cam. They say the bottom end will be good for 1000+ HP and I am shooting for 600,so I hope to have a dependable bottom end with low maintenance .I still need some help on picking a head ,I am looking at the 227 AFR or the Brodix Track 1. Let you know how it turns out.