[Dark_5.0]

In theory your fresh 306 can and will handle a properly set-up 175 shot. However just remember that the bigger the shot the quicker your motor will go boom with a lean or timing condition.

I have seen guys successfully spray 250 shots on a stock short block.

Its all in the tune. Think about it, 99% of the time when a nitrous motor fails there is a hole in the piston due to a bad tune. Very rarely will you see someone split a block.

Good luck,