Sent my heads (Vortec 062's) to the machine shop to the have the guides machined for a higher lift cam and LT4 springs, he recommended machining for screw in studs. I asked him what studs he recommended, he said just get ARP screw in studs for a small block Chevy, said it would be about a week to do all the work since they were backed up.
Three weeks later, and after I told him I needed the heads so I was gonna take them to another machine shop to get them finished, I finally picked them up this past Monday.
Get em home, take them out of the bag, get them snugged onto the engine, and I start installing the ARP studs. Now I notice that the rocker stud pedestal isn't machined, they just pulled the studs and tapped the hole. I do a trial install of one stud and rocker arm, and sure enough, the rocker arm won't go low enough for the pushrod to even touch it. We're talking at least a 1/2 inch gap.
I call a performance engine shop in Amarillo, he says the way they did the machine work was for "old school" screw in studs, not the new ARP style.
Rather than take the heads back and lose MORE time, I ordered some of the screw in studs that don't have the hex shoulder, so I should gain back my needed clearance.
Isn't it, or, wouldn't it be part of machining a head to accept screw in studs to machine the pedestals down (I was told a minimum of .400 inch) to keep the geometry where it needs to be?
This is the first time I've had a set machined for this, all the other heads I've had already came with the screw in studs already installed.

 

The kind that don't need the pedestal machined down are only repair studs - like for when a pressed stud pulls out. Performance studs have always had to have the pedestal machined down, because they have a hex in the center of the stud that gets torqued down to the head. This is how its always been done on the SBC since they started using screw-in studs in the early '60s.