I.D. 340 parts

I picked up a disassembled 340 today which the owner did'nt have any history on except he was under the impression that the motor was original to his car which it was'nt.I'm not sure about some of what came along with it so hopefully someone on here can shed some light on it.

The motor is a cast crank 73 with one '3418915-G' 'J' head (two 'J's by the spark plugs) and another head with a 'J' on the underside but not by the plugs and has a different casting # (3671587-E).Is that basically a later version of the same head? The intake ports measured out the same and both appear to have similar valve sizes which appear to be 2.02 intakes and 1.60 exhausts but I was'nt able to measure them too exactly.

Also included was an edelbrock D4B which I'm not familiar with.I measured the ports and they're the same width but shorter than the ports on the head.Is that intake built for 318 size ports? It's a high rise piece and looks like it should flow decently.