It was made by the same manufacturer that made Champion chassis. Who this manufacturer was, well I'm not in a position to know.
Rick,
ALL those chassis (Champion, Riggen, Mura, Phaze III, Cobra...) as well as the British chassis by RIKO, BMW Models..., as well as some Spanish chassis by Segura, were produced by AYK/Aoyagi in Japan. AYK made them all. AYK also made chassis for their own Japanese consumption, here are three examples, one using the same parts as supplied on several of the Champion chassis:
These two are Spanish, but also produced by AYK:
Nothing too surprising here, because once someone begins looking at the American slot cars produced from 1965 through 1972, one find that nearly 80% of the parts were actually made in two places: Japan and Hong Kong...
If you look at Rodney's chassis, it does not have a Champion motor bracket but a Cobra/Phaze III unit, and its design is very similar to other Cobra/Phaze III chassis issued in 1968, after the angle-winder "revolution", making it rare because it was possibly not even issued for sale, and what Rodney has might be a sample obtained somehow though the Cobra/Phaze III people, possibly from a distributor...???
The LASCM has an almost identical example, but i need to take pictures of it.
AYK produced whatever designs were given to them by the various manufacturers, and like Igarashi for the motors, was secretive in communicating with each, so that Champion did not know what Cobra was doing and vice versa.
I had a heck of a time making some sense out of it, but eventually was helped by some of the older gentlemen that ran Aoyagi in the 1980s when they were deeply involved in R/C cars.