[Mr70]

I don't think many people ordered an L-78 Chevelle with a 4:10 rearend in 1970,regardless of bodystyle & that includes Elcaminos.Maybe it only being available for the first 90 days of production had something to do with it..
The majority of them seem to have been built with a 3:55,either open or closed.
So far I've only been able to find 3 real L-78/4:10 convertibles and 8 real L-78/4:10 hardtops,as compared to 211 L-78's of both bodystyles,including Elcamino that all received a 3:55 ratio that year.
The three 4:10 convertibles are manual trans.,and only two of the 4:10 hardtops are auto. trans.