I dunno how hard it would be in your area to title a non-titled bike. If it had a title, I would say a great 1st bike. The SilverWing was a loaded touring bike w/fairing, luggage, & more. There were also turbo 500 & 650 CX's. The first out was the 500 and at the time it was the most technologically-advanced Honda on the market. The engine bore little resemblance to the carb bike.
If you know how to get it titled, offer him $400. That's more than he's got into it w/the MAC exhaust & the repairs, if he had the work done at a shop.
I think there's a spec-class for boat racing using the transverse Honda V-twin engine, in Australia.