Isn't another indicator its an earlier engine is the coil centered with 3 plugs on the left and three on the right? Later (at least on my '53 235) the coil is not centered but has 2 plugs on the left and 4 on the right.
earlier engine I I I coil I I I
later engines I I coil I I I I
I = plug
My money is on a 216 truck engine... but hey, I've been wrong before and I'll be wrong again. Probably before the sun sets today.
