I am surprised to an extent that no one has mentioned Allen Brown's excellent site --
OldRacingCars.Com -- during what little discussion there has been on this thread. Lots and lots of "Eye Candy" but little substance for the most part.
Thought it interesting that a discussion of F5000 began with a few photographs of a USAC Championship car, an Eagle, rather than a pukka F5000 machine.
Liked the notion of F/A or F5000 from the beginning, but its last season or so in the US was a bit painful to watch at times. The US series was as much of a victim of the declining fortunes of the SCCA as the original Can-Am and Trans-Am were, the club's governors wanting to return to the nostalgic past when it was an amateur organization and run like a gent's club. Its attempt to revive "Can-Am" by putting bodies on the F5000 cars was an interesting one, but missed the mark by a wide margin. The IMSA Camel GT series was now the game in town and the SCCA simply could not find a means to truly compete with it. The departure of USAC from F5000 after the 1976 season was another factor, with USAC having its own problems to deal with at the moment.
Just an observation.