I would not go over 6500-7000 on a cheap crank, hydraulic lifter set-up. If it is a race-type motor, ie aluminum rods, solid lifters, good crank, shaft rockers, good springs, etc, let it sing up around 8500-9000. Depending on the cam specs, it may or may not make power to a safe redline.
I had a 392 Ford Windsor, hydraulic lifters, nothing too fancy, and it was safe up to around 7000.