Need Help - Lifters Collapsing on 302

Friends 66. If he exceeds 5,500 rpm or so, it collapses lifters. As long as he keeps the rpm down, it runs great. The only other symptom is lots of lifter clatter on a warm restart. Clatter lasts for about a minute. Oil pressure is good, running straight 30 wt.

What I remember about the motor:

Stock 302 block
Either the B or E roller cam (can't remember)
1969 351 Windsor heads
Stock rocker arms
Not sure about springs or pushrods

Local shop built the motor.

Any ideas?

I'm getting all of this second hand, so sorry for the lack of specifics. Car started missing badly a few months ago. Returned to place that built the motor and they told him one (more?) of the lifters had collapsed. I haven't seen what's happening, but I assume the internals are torn up. They replaced. Not too long after, same deal. This time he had to pay. They said something to him about overrevving, but he has a MSD with rev limiter. At the time it was set at 6k. Now he has it set at 5k and no problems, but he is missing a big part of his powerband. I'm thinking that the valve train, assuming it's set up correctly should handle 6k rpm with no problems.

I was wondering if the springs could be binding and causing damage to the lifters, but why only at 5k+ rpm? Could they have used push rods that were too long? Personally I'm voting for a problem with the springs, but I'm not sure how to diagnose.

He has lost confidence in the guys that built it because they seem totally clueless. Do you see any problem with the combination of parts? I kind of wondered about the early 351 heads on a relatively late model 302 and if there could be a problem with the combination that got overlooked.

Your help appreciated.

It's the geometry I'm concerned about too, but I don't know squat about Ford small blocks. It's a roller cam, so wear on the lifter bottoms shouldn't be a problem. I'll suggest adjusting the valves. I assume that the late model roller-hydaulic lifters are good for more than 6k?

Thanks for the suggestions. I'll keep an eye on the thread so throw an idea out there if you have one.