My 517 routinely spins 6800+, went 7200 more than a few times. It has a Bullet 264/268 @.050 Hydraulic roller with the Crane lifters....BUT(!!!) These Heads also have the Race W2 Style billet one piece Shaft hold downs (Chapman stage VI's) which are much stronger and more stable than a Cast-In-Head Pedestal....and ports that are happy to feed it up there. Never rev'ed it higher than that...but with the new ported 337 intake it may want to go even a little higher.

I'm not sure it would rev that high or that stable with cast-in pedestals....I can't say 'cause I never had a 500" BB willing to rev this high. I do know the fact that they are Hydraulic rollers don't seem to hold it back at all, this one rev's just like a Solid roller. I think the HR (or any valvetrain) ability to rev has about as much to do with geometry and stability (and minimal oscillation) as it does with sheer mass.

all else being equal one would think a low deck might rev a little higher than an RB....the pushrods are ~3/4" shorter and proportionally a bit lighter.