When to switch to screw in rocker studs?

[scouthead]

POsted in the TBI section also, but for anybody hanging out in here...

Rebuilding my 350 in my '88 blazer... been on the phone with comp cams lately... I want to put a roller cam in my motor (have everything but the cam), and am trying to find out what my stock valve spring pressure was supposed to be, and how much pressure the press in studs can handle before they start coming out... not finding anything while searching. Anybody got anything on this?

 

[bigblock72]

The general rule I go by is; if it needs the spring seats cut then it needs screw in studs. You'd be hard pressed to find stock diameter springs that would have enough pressure to cause problems with pressed in studs.

The only time I've seen problems with stock studs and springs was when a customer installed 1.6 ratio rockers on a larger cam which bound up the springs and also the retainers were hitting on the guides. The bent pushrods weren't enough clue for him so after replacing a number of pushrods he couldn't adjust the valves anymore because the studs were working their way out and he brought it to me.

 

[TerryD]

I have seen two small block chevys with stock springs and rockers pull the studs out of the head. If I have to take the heads to a machine shop, then I go ahead and pay the little bit more and run screw in studs.