Interesting point TJ. I wonder whether March were a special case, building chassis for the works team, plenty for customers, upgrading models, holding loads of spare parts etc. Do you think the 'eight or nine more' were built from genuine, contemporary parts that sat on the Bicester March HQ shelves?
The March 761 was a strong performer for some of the 1976 season but according to contemporary reports it tended to wear out the tyres produced by Goodyear later on that year. This is not a problem in historic racing, of course.
I can believe that March held a stock of spares for the 761 a few years after 1976 given that a few customers still used the model or its sister models. I can believe that there were a few bent chassis for the 761 collecting cobwebs in lockup garages because the economic value (at the time) was negligible. I can't believe that resurrected bent chassis account for more than one or two recreations.
One car that interests me is chassis 751/3, Vittorio Brambilla's car for most of 1975 including the Austrian GP win. Oldracingcars.com records this car as "written off, United States GP 1975". Brambilla finished that race, on the same lap as the winner. He is reported as having problems in the race but unless I have missed an accident on the slowing down lap, the car was complete when March packed up their kit. The car was raced hard that year and I can see why it may have been seen as the "most worn out" of the 751s.
Another interesting car is 761/7, built for Willams Grand Prix Engineering for Patrick Neve to race in 1977. This is the car which allegedly had a layer of orange paint on the monocoque which allegedly made Williams believe that it was a second hand car.
I'd like to know what happened to 751/3, the first works March to win a WDC GP. And whether any of it was used for 761/7, the first car raced by Williams Grand Prix Engineering.