I wander why none of the three companies i have talked to has mentioned that it takes a longer stud with roller rockers. Even when the set was bought it wasn't mentioned. That was when i had the heads off and could have done it easy.
One person i know changed from original stamped steel to roller types and did not have to go to a longer stud.

I'm just trying to make sure something else is not wrong before I have to pull the heads (that i just put on) to drill and tap the 3/8 out.

You're also going to need to spend another couple hundred dollars for taller valve covers too. I think the pro comp steel rockers have the roller tip but still use the bushings and work on the stock stud.

I just put full roller rockers on my 502. Biggest pain in the ass dealing with new push rods, new valve covers, and chasing down the correct poly locks because Summit sent me a kit missing parts (that's a different story). At this point I should've just stuck with the stockers, lol.

Well i've just spoken to two performance engine builder shops and both said that nothing should be needed to make this change to the roller rockers and if using the 1.90" studs. If there's not enough threads above the rocker, something is wrong. No need to go to a longer stud. That would also require to drill the guide plates or use adjustable guides.
I will keep looking at it. Going to get another pair of eyes on it.

Dumb question, but are you certain the valve you are working on, that the lifter is on the base circle of the cam when you set the rocker on there?

Also sure you got the correct # rocker for a big block chevy?

At this point I don't think there is a dumb question. Something sounds completely messed up. Can you post some pics or send to someone via tx so they can post. I've run into some weird chit over the years but... I can imagine mild thunder hated to even write his last post but sometimes you just gotta ask those questions as everybody has different abilities. I have a feeling it's an oversight. Walk away and come back and look at it again. I saw a great engine builder that couldn't get the distributor to drop in all the way. After several aggravating minutes for him I had him pull back out. He had the gear on upside down. True story.

Another possibility. The pivot shaft on the rockers. May have a high side and a low side with a flat machined for poly to seat against and might be flat facing down and poly seating against rounded bottom side...

at least were all coming up with something.

Mildthunder... yes im on the base circle. And part # is from engine Pro #1114. He says there is only ONE rocker from his company for a BBC. I feel like ordering a different brand. May go to a local engine shop tomorrow and look at various used rockers to compare the trunion size.

DereknKathy... are you talking about the small flat machined recess area on one side of the barrell(trunion) on the rocker? Yes i have looked at that. All cylinders are doing this identical.

Good questions. I dont mind yall asking as i do have limited experience, but getting good advice from a relative with mega experience. So far, things are just not adding up.

We just put the old stamped rocker back on just to look at it. It pushed the lifter down about 0.050"(about equal to one thread on the new adjustable rockers) when it bottomed out so that looked about right. To reach that same spot with the engine pro rockers we are at only 4 1/2 threads .. a little less than 1/4" ... not enough.

I will take pics.