So I scored this AMC 401 and spent a good couple hours attempting to get more info from the block and head casting #s. This is what I know so far. This specific mill came from a early 70's wagoneer Block# 3198951 Heads# 18202 Tag on valve cover# 906Z30 All these tell me is the block is a 71-77 year. The letter "Z" on the valve cover tag is supposed to tell me if the cam bearings are under sized or if it was a factory over-bore, or something to that effect, but all I found for that letter is conformation of year and engine size. I will post some pics of the #s I found. My other question is about the trans. The pic shows the pan being stamped a GMC product, And I do believe it is a GM turbo400 but with the AMC bell housing bolt pattern. If I'm correct, is there a specific tail shaft I need since this was behind a transfer case? And do I need a short shaft or a long shaft? Let's load up some pics (sorry for the bad pics, my pain meds were kickin' in) P.S. I learned a bunch of interesting info about these engines (forged crank and rods, poor oiling system, blah blah) but if there is anything else you could add to aid in my quest for knowledge, I'm all ears. Thanks guys!