B23FT max rev's question...

I'm sure this is answered somewhere, but I couldn't find it.
What would you guys say is a safe number for max rev's on an unbalanced B23FT at appx 20psi?
I'm finally getting around to cleaning this motor up for install into my 242 and don't want to disassemble the relatively low mile (~150k) motor for balancing. Plus my budget is super tight.

6500

I'll take 6501 bob

When we raced our n/a b23 with a RSI stage 1 cam we did not see much more power past 6k and set our shift light to 6200. Any more than that it would make alarming in happy noises. It has gone through 6 16 hour races of rpm's ranging from 4-6k without a hiccup. We never took the head off the car or did anything else beside oil changes. It had 13700 miles on it before we turned it into a racecar