Made a static pressure tester for my fhead block. Don't know if its an accurate indication but it should show if there are any extreme internal cracks . Better to check before sinking any bucks into it
Havent had it magnafluxed. Probably a good idea. There are most likely key areas where the old flatty likes to crack. Flatcat would probably know for sure!
if it holds pressure for a 24 hour period Id say its not cracked . 50 psi is a bit more then I would of felt comfortable pumping into it. but thats just me .