I road raced for thirty years or more, raced WERA (the greatest bunch of racers ever), AMA CCS, AMA BOTT, and some other AMA stuff – but not AHRMA. I have nothing good to say about AHRMA.
I tried racing a CB750 in 1976, but was not competitive no matter what I did to the bike. The trick back then was to buy a Yamaha RD for $150, put some good tires and shocks on it and go racing. I can’t remember any SOHC Hondas doing very well, although some of the twins did better later in vintage racing. The DOHC Hondas did well with guys like Freddie Spencer riding them, and even the Honda Interceptors did well once Honda starting paying win money. I road raced a Honda XR500 years ago, did o.k. with it and had a lot of fun. It was actually my ice racer with some sticky road tires on it and a front brake; fast, light, and indestructible.
Some of the Honda twins are very competitive in vintage racing today. That’s what I’d be looking at if I wanted to vintage race again, or just do track days - a Honda twin.
I still like to get to the track once in a while for track days with Sport Bike Track Time and the Ducati Owners of Canada. Check them out, both are excellent. Sport Bike TT probably does track days near you. For information, besides WERA vintage, check out Vintage Road Racing Association of Canada. The VRRA site has a lot of good and interesting info, good guys there too. Probably the best help is to hook up with some other guys that are doing track days or vintage racing