I ran one for three years in my 383 drag motor. I would say keep it under 7000 and use as light of a piston as you can. I was using a 5.7 rod so my pistons were a little heavy. Went to 7000 a few times and never had a problem. Car didn't shift a few times last year and my limiter caught it at 7400 and I had 4 pistons tagging a head. I always saw evidence of the crank moving around more than I liked but nothing that caused a problem other than I didn't care for how the bearings looked. Good crank for the money though. I went 9.509 @135 with that motor. 550 would be the max for it though. IMO I've gone to 4340 so I could lean on it a little and not worry.
Curtis