The other thing to consider is the amount of heat that the oil absorbs and has to displace that would have been taken care of by the coolant on non simemez cylinders.
SB 400 would wipe out rod bearing real easily if run much below the add mark unlike other small block that survive as long as there is a couple qrt in it!
I replaced many knocking 400 with target master 350 in the early `80s, knock the big weight off the flex plate & install new damper as 400 is externally balanced.
