The 70 440-4 would be internally balanced engine.
Are you sure? I have a 1970 440 HP single four barrel engine that has what looks like the 3512017 damper for the externally balanced engines.
http://www.440source.com/dampers.htm I can take a photo if it comes to that.
I stand corrected, though it is funny the same 440 source notes, state that later 72 up motors using heavy rods did not use the 6 pack balancer. Regardless of rod (heavy or normal) with steel crank a neutral balancer was used. So a combination of heavy rod and heavier 6 pack piston meant external balance with steel crank.
