For whatever it is worth the breakover from engine serial nrs starting with VAC to A47 occurred during the 1949 model year. If it has a Eagle hitch or a place to bolt the rock shaft, it is an early 1949, if not it is somewhere between 1946 & 1948. The earlier VAB engine serial nr also overlaps VAC 1946 - 1948.
This is just my opinion gleened from the parts manuals and comparing a limited nr of engine serial nrs to the tractor model nrs so the advice is worth just about what you are paying for it.
Disclaimer: if the engine has been swapped out, all bets are off.
Joe
