There is no motor into other than the cubes and the cam.
It could be a 10.5:1 motor with unported 516 heads, or a 15:1 B1 motor.
Without knowing what the build is, it's certainly possible the cam is too big, which is why I suggested a compression test. If it pumps 125-150, the cam is too big. If it's 190-220, it's not the problem.

Essentially no useful motor info has been provided, nor has it been confirmed whether or not the two new converters were actually built for this particular combo, or if they were simply "new".

IMO, not enough pertinent info has been provided about the overall combo to make a real recommendation.

In any case, he said he was going to Norwalk this weekend, so I'm sure he'll get plenty of suggestions there.