The recent posts of several USAC (ARCA didn't race at Michigan in the early 70's) cars got me motivated to look through some old race programs. The # 14 was found a few years ago and restored. It started life as a Cotton Owens built Superbird, but was only used as a backup car and never raced in NASCAR. It was purchased by Pierce Auto Parts and raced in USAC. Wicked fast, especially when driven by Larry Moore. Moore won a race in it (1975 I think) and a pole for the race this program was from in '76.
The #34 was built by BEMCO. BEMCO was owned and operated by a guy ( I think his last name was Bemmister) that had worked for Nichels Engineering during the Chrysler years and started his company after it ended. He built A LOT of really fast short track cars, but this (probably under-funded family-run) Charger never had much success.
By the way, when I was double checking the USAC/ARCA thing, it appears the Michigan 200 mile race (run later in the day after a indy-car race) paid over $8k to win. A few years later winner got about 25% of that.