I'm running a Crower Solid Roller (16462) with .581/583 and it had plenty of room, but it is on a 110 and the .050 numbers are a bit shorter than that Comp.
I suspect it will be fine, but as always CHECK IT!!!
There was mention of possibly taking .015 off the deck and using a .020 gasket. That could easily add up to .035-.045 less clearance which is alot. SpeedPros, at least from my experience, do not have very large reliefs. If you have to modify the pistons, make sure the crown is thick enough.
The factory cast 390 cranks were fine for 7000+ rpm nascar racing in the early 60's, the failure they had then was due to insuficient oiling at those rpms, not the cranks, from all I've read. I'd have no doubts about spinning one that high, as long as the oiling problems were addressed (as in using one in a side oiler 427 block)
One thing to bear in mind, is that with a motor at + deck (piston down in the bore) and a haed gasket of anywhere from .02 to .04 you can have a chamber that has less squish than a mid 70s smog motor..... (NOT GOOD)
No squish equals no turbulance, which leads to hot spots, detonation, backed off ignition timing, piss-poor horsepower and lazy throtle response.
IMHO you are far better off to deck the block and have to flycut the pistons than to run a motor with no quench (or too little at any rate).