That Fireball cam is an old school grind that requires a converter in the 3000 rpm range.
What I have found after messing with a few of them over the years, is that early ones are indexed from the factory to be split overlap when dot to dot.
Some, and I assume them to be later versions, are indexed to be 4 degrees advanced dot to dot. I have one in 440 that is set that way.
That 4 degrees will make a big difference in the way the engine is able to climb on top of a tight converter