Mine Have been good to 6800+, hit 7200 a few times and feels like it could go higher. But If I'm shooting for 7500 my thoughts are why wouldn't you go with a lighter Solid Roller? i learned a lot about HR's from the mid 90's tuning on the Pro 5.0 type set ups where you had to run HR by class rules. Bullet was on the front line of that market and were always putting out new grinds to try back then.

Careful attention to valvetrain geometry and a very stable shaft foundation (my heads run a W2 style billet blocks instead of as-cast pedestals) I think helps a bit. And the Bullet desined HR lobes combined with the early (pre Chapter 11) Crane Lifters have worked very well for me is all I can say. I'm running long 11/32" stem x 2.25" intake valves which I think are lighter than the 2.14" x 3/8" stem mopars (the only BBM I can compare to from expereince).

But if Bob is saying there are issues I have no doubt there have been issues.