I'm surprised it didn't start floating valves up in that area (or maybe it did). I've heard of guys revving them up in the 5500rpm range before too. I know Elite is building a puller now to rev safely up to 6k.

 

I saw that elite is making high rpm oil pump for 1500 bucks, its just the 2 gears. It was a little out of my price range so i just bought the pump from the dealer for 70 and will be more careful. It may have revved even higher than 4500 on the last one (it sounded pretty crazy)

 

I've had those RPM's a time or two as well, when my trans was going out, there were a couple times I was WOT and it missed shifts, I know one was close to 5k. There used to be a guy on powerstrokenation who threw a rod through the block on his turning 5500 street racing it .