On most CACC race weekends the Vintage club runs it's REVS series, and the criteria is considerably different than for the BCHMR. For the BCHMR pretty much anything 20 years and older is acceptable, as long as it is prepared to the rules of the day (a 1970 Datsun 510 should be prepared to the rules for 1970). It is very likely your 510 would be accepted for the vintage grid on any weekend, however it would definitely qualify for the BCHMR.

It would be best for you to attend VRCBC meetings and talk to the members if you live in the Lower Mainland, any of us would be happy to to answer questions.