FWIW, Don, that "'73" motor is actually a 1972 vintage, low-compression 1296. I'm somewhat sure the original valve covers on those were silver, but then valve covers are very easily to a: swap or b: paint! On the other hand, the '80 engine is a California engine, which confirms my (failing!) memory that the California-spec. engines had blue valve covers (but then, see a: and b: above)!