Technical Early Pontiac Rocker Arms

I bought a ‘62 Pontiac 389 short block and heads to rebuild to replace the aging ‘59 389 in my Studebaker pickup. It’s missing some small parts including the rocker arms and balls. After looking through online catalogs I’m somewhat confused about what rocker arms I need. We did upgrade the studs to 7/16” screw in studs. The cam and lifters is a mild Comp Cams XE 262 so it can oil through the pushrods (that I haven’t ordered yet).
Are they dimensionally the same as SBC? I’m fine with stock type stamped rockers or upgrading to roller tip but with no stock rockers to compare to I’m not sure what to order based on the catalog specs. I’m probably over thinking this, any suggestions?

 

Roller tip is senseless .

 

Won’t work Bob, SBC rockers have a shorter OAL, even if the pushrod fit the rocker properly the rocker wouldn’t contact the valve stem.

 

Do the later Pontiac rockers interchange with the earlier ones? I have several sets of what I believe are the later Pontiac rockers.

 

Same offer here on later rockers if they can work. I have a few sets I have no use for and I would be glad to send a set.

 

I think @Jeff Norwell works with Pontiacs, maybe?

 

Yeah, I don’t have any stock ‘62 rockers to measure. I guess I should check eBay for a stock one so I can do my own figuring. I’ll do that. I do have a set of stock rockers for a 68 400 but I think the balls are for 3/8 studs. I’ll check. In hindsight, I probably should have left the stock studs in the heads, it’s just a workhorse, not a race engine. I guess I read too many magazines when I was growing up, lol.
IIRC, didn’t 396 Chevys have studs that are 7/16 into the head and 3/8” on the rocker end? Maybe changing the studs would allow me to use the later Pontiac rockers.

 

Looking at Summit there are a lot of screw in stud options so if the later rockers are the same general dimensions they should work.

 

Not sure on the BBCs, but for a SBC the stud is pulled, then tapped to 7/16th.
I’ve a set of screw in studs. 3/8th on top, 7/16 in the head

let me go verify

 

I won’t be using them, if you need them, will send your way

 

Here’s the box

 

http://www.wallaceracing.com/interchange.htm

 

It occurred to me that I might still have a ‘62 Tempest rocker arm and stud on the shelf out behind my shop leftover from my Tempest project. Sure enough, there they were. I’m assuming that Pontiac used the same geometry and therefore rocker arms on their 1/2 of a 389. They had bottleneck studs that were 7/16 where the ball sits and 3/8 nuts. My later model rockers also use 7/16” balls but have 7/16 threads. Dimensionally, the old Tempest rocker looks to be the same but the slot is slightly longer in the later rocker.
So it appears that the later model rockers and balls will work on my ‘62 heads with the new 7/16 screw-in studs.
I want to thank ’51 Norm and Guthriesmith for their generous offers. And everyone else for getting me to think outside the catalogs.
I’ll put the heads on and measure the pushrods and see if I can confuse myself again.