Coolant leaking into 318 cylinder 8
When I had the 'Killer6' block done .060" over in '86, one hole was porous, & had to be sleeved. That block would've been ~20yrs old at that point, now it is pushin' 60, time is not kind....and flawed castings are still out there waiting to be "discovered".
Every old mill should be sonic checked & pressure tested. Luckily, Carl spotted the warning sign as He progressed, & sent Mark over to let Me know & decide.