Don't know much about 624 heads but I've heard they're prone to cracking. I think they used to be called Smog Heads back in the day. Unless of course yours are GM performance heads. Could be wrong, I've never rebuilt any GM V8s.jdansmith wrote:yes,its a 350, 4 bolt, aluminum intake, Holley reworked the carb 830cfm 624 heads, .30 over ,flat top pistons, timing around 36 degrees, and running a t200r4 transmission.