Quote:

The 510" lift max of the stock springs is probably due to the fact that the heads are a stock replacement type head- and compared to stock cams a 510 lift cam (509) is much much bigger/aggressive than stock. ???



That makes sense. I guess I don't consider them a stock replacement head.

1968 Roadrunner 383 auto .060 KB 400 domed pistons, Stealth heads, Torker intake, Holley 830, Lunati Voodoo cam 276/284, .513/.533, TCI 3500, 3.91 gears, all ARP fasteners,