318 combo help

I'd like to address the HARD BLOCK issue. Maybe someone can chime in if I'm wrong on this. I thought "hard block" was when they filled the water jackets with basically cement to give a drag race engine's cylinders more strength. If that's the case I've never heard of one living on the street with no water around the cylinders. I think I read this in How to hot rod a mopar small block. I'm going to try and dig it out and check.