BAD-HABIT

A couple of questions...First how do you check for correct geometry on your rockers....Second which ones will fit the centerbolt valve covers. Third I would like to switch to 7/16 studs at base and top so will any of those fit? Im already running now and I have about 20 hours on the motor so is there something I can look for on the valves,studs or rockers to determine if everything is ok. I mentioned in a recent post about breaking a ARP hardened stud off on the top half threads and would like to make sure this was just a freak thing. I have been told to run 7/16 threads bottom AND top. Currently the base is 7/16 and the top is 3/8

"Bad-Habit"

Iggy

Funny I was just looking into the same thing (roller rockers).
I found several that require tall valve covers and wondered if they'd fit with the exh manifolds.
Saw an article on Chevy High Performance's web site archives and they were using GM's rail style, 1.6:1, full roller rockers (no guide plates needed) and I thought they fit under stock covers. So, I went to GM Performance Parts and looked them up. Several types listed required tall covers but these didn't mention it so I guess they don't. And the price wasn't all that bad.
I don't recall what size studs they handle but bigger is always better.
As for breakage, you could pull yours and clean them real good then look for cracks under a magnifying glass, but you might not see them. Magnaflux or dye penetrant is the only real way to tell.

ROLNTHUNDER

The size rockre studs you have are good, you can use roller tip rockers under the stock covers and i think crain makes full rollers also, they are self guiding gold no guide plate needed.

traviss

Here's my info.. I built my 383 over the winter and used the vortec heads. I had the heads machined for screw in studs, guideplates, bigger valave spring pockets and guides needed to be machined to.. I used the Crane Gold roller rockers that are called a "narrow body" rocker and 1.6 ratio, they are 3/8" they don't make these in 7/16". My studs ARP are 7/16" bottom 3/8"top, Plus because I used the screw in studs and guideplates I needed the "non self aligned" roller rocker. Not to cheap at $299 a set. With my 1.6 ratio rockers and vortec heads my pushrods hit the pushrod holes, so had to enlarge those

My stock vavle covers fit, all i had to do was cut the upper side of the inner supports of the cover, they work great..

I think your stud breaking is just a flaw in that piece, unless you have a lot of pressure on the stud itself.. I heard that your valvetrain geometry is correct when at 1/3 the lift the pushrod and rocker are 90 degrees to each other.. any questions let me know