You will not need 30psi to see if it is leaking , half of that will be more than lots . good luck

Thanks guys thats good to know, I will try 20 PSI and see what that does. It seemed like 30 PSI was the water pressure when running not sure may have been 25.

I have yet to see the freeze plugs push out and the block not be cracked. I hope for your sake that it isn't cracked, but I'm not holding my breath. Most of the time they will crack in the lifter valley. Good luck. Let me know if I can help.
Eddie

seen several pop out and not crack..one guy did not find out till after running for some time, noticed sluggesh performance, boat was full of water..bilge pump not working either..had popped the one out behind the starter..but block was fine...

Good news so far, I drove the freeze plugs back in. Capped off all the open ends, filled with RV antifrieze, added 20 PSI of air and no leaks.