Well I got my heads back from the machine shop today.They are 462 castings,2.02/1.60 stainless valves,bronze? guides,surfaced, .500 lift springs,59cc comb.chambers. They are tapped for 3/8 screw in studs.CR is 10.4:1. They were bare castings when I took them in,so my mach. shop guy went all the way through them,except studs and guide plates, as i was already looking at divorce if I spent 1 more cent,LOl What studs should I use? It's basically going on a street/performance application,350 4-bolt SBC .30 over w/dished pistons,pretty much stock short block. The cam is a Melling C-400-P Hyd. .447 lift/222 dur.Just wondering if I need to use guideplates also.I'm thinking ARP studs,probably stock size,don't really know.Anyone have a part number,that would be greatly appreciated.