Gentlemen, thank you for your very encouraging words! This was an especially satisfying article to work on. The light was very good at Seattle for photography that weekend, and it seemed I couldn't take a bad photo of the March if I'd tried. Also, I had a brand new gadget that helped tremendously: a digital voice recorder!
Wayne Lee is correct that there are indeed conflicting records - or at least conflicting memories. What I included in the article is from two (recorded) interviews of Wayne Mitchell. Before I talked to Wayne, I'd thrown together a very preliminary write-up which included Jim's information and also production numbers from the Mike Lawrence book. Wayne dismissed the production numbers right away and said (highly paraphrased) "I don't know who Mike Lawrence is, but I should know better than anyone how many cars I built. I built about fourteen March Formula Fords over a period that included 1971 and 1972... and whether they were 719s or 729s is just a technicality because they were all similar." The Marchives only give Wayne credit for building seven cars - all of them in 1972. Wayne was also very specific on the point that he built all the frames and bodies he used. I double checked this because I had seen the "AM" number stamped on Jim's frame... if indeed March provided Arch Motors built frames to him, Wayne doesn't remember them. I don't have a horse in this race or an ax to grind but my suspicion is that the written records are probably wrong and Wayne's memories might be less than crystal clear too. (It's been a long time!) I'm aware that at least one other (U.S. assembled) March 729 appears to have an AM series chassis number, as described here:
http://www.motorsportretro.com/2011/...-formula-ford/ (Note that the seller is presenting it as follows "The chassis has a unique number 'AM72-4' stamped on a rear suspension component. This denotes that the chassis was the fourth made by Arch Motors in 1972 and the first to be imported into the States... 729-1 is the first car (of 11) produced by WME.")