Not really. The 240 and 280 Z's are easy to distinguish from each other. The size of the 280Z was over one foot longer and had a sportier look. The 240Z and the 260Z were almost identical.

The 240 and 260 used carburetors. The 280 and all later Z's were fuel injected. HP was about the same between all models except for the Turbo model 280ZX, which was available from 1979-1983.