Old post, but I ended up buying the 73 motor and it bolted up fine and is still working.
From memory the only difference was the size of the slot for the crank arm. I seem to remember the newer motor had a smaller shaft size (flat part). I cut a small shim and added it, but I honestly don't think it was needed.
Buy it local and try, if it doesn't work you can return it.
cnxt,
Thanks for the info. My local parts store has one coming this week. It is a A1-Cardone re-manufactured unit, part# 40-382. It crosses to ’72 Charger.
*After looking more closely at the 71 vs 72 crank arms – I agree- they look just slightly different, but nothing that a small modification (aka: like you mentioned: a possible shim) would make working fit.
I will post an update, after I try this conversion.
Thanks,
-miker71
* Attached pics: photos of the ’71 (2822290) and ’72 (3431553) crank arms *