It is definitely a good idea to drill a small air bleed hole in the stat body, but never remove the core!
Like you say, Blackwater, the coolant doesn't stay in the rad long enough to be cooled.
I've tried MANY different things to correct a cooling issue on my old 69 Charger.
Water wetter additive had the most significant benefit over all I tried! (I was 19 at the time and could not afford an aluminum rad).
