Most common place that I've found cracks on SBC's...is above the lifters, on the inside coolant passage wall. If you take the intake off, it would be between the head and the lifters.
Quite often, it cracks in a horizontal line, about 1.5" or so above the lifter bosses.
That type of crack is generally from an overheating condition.
The other type would be a freezing crack - which is generally found on the outside wall of the block. I usually see those not far from the freeze plugs...especially near the motor mount.
Seems like if it was on the outside - you'd have a real obvious puddle under there.
Hope you get this figured out.
