There was a group that listed a CNC'd aluminum water inlet for amc's a while back for $100. They still list other products- I'm going to call and see if they can still produce the amc. I polished the timing cover for my 401 much like you did you intake. From now on I think I'll buy them that way. It is a lot of work!
72 wagoneer- My first FSJ
89 G-wag- built 401