How much HP or Rpm can a stock bottom end with stand

Thanks guys
I did think the rpm was a big factor so that's why I try not to spin it too far even though it's soooo tempting as my engine is still climbing in hp at 6500rpm.
Before I had a 360fwhp engine that gave me 270rwhp so I lost quite a bit. So now I have 430rwhp I am guessing I must be around 550fwhp now roughly. I wouldn't mind giving it some nos or e85 or more boost at the track but I have to find out what will work best for me as I have no intercooler and currently running 8 psi. Not sure what max boost I can run. I need to read up on it I think