When I repowered my bus back in the '90s, all the big block Chevys had problems like this (at least all the ones I saw in wrecking yards, etc) and they were expensive even as cores, because Big Block Chevy. So I went with the Cadillac V8 instead. Lighter, stronger, meant to be 500cid from the get go. Plus torque and plenty of it.
When I brought my Dad's old Cadillac work car home after he died, the gauges and such didn't work. By the time the STOP ENGINE TEMP light and buzzer came on, two miles before the exit with my wife driving it, there wasn't much coolant left in it. So after I fixed the blown out hose in a McDonald's parking lot in Meridian Idaho, I let it cool down. Then poured new coolant back in it, and drove it home and then for another couple years.
