NOS LA timing cover super nice. 3769966 timing cover fits 1976-1990 all small block engines, 318, 360. Will fit earlier years but the timing marks are on the wrong side. Selling for a friend asking 140 and the ride. Shoud fit in a FR Game board box.
FYI...also won't fit with early cast-iron water pump...timing marks interfere with early lower rad hose location.
Really, I haven't run into that situation, and I've had many early engines with later covers. The OP's cover is appearance correct for the '78 and newer models, but, will fit and work fine for the '70-77 models. The only difference (not counting date codes and logo location) is that the one posted can have it's seal replaced without pulling the cover off.
Covers went from having a separate bolt on timing tab in 1968 on the pass side. 69 it was cast into the cover but still on pass side 1970 was first year on the drivers side.
I used the early pump on that cover. it was tough to see the marks but doable if you aimed the light just right but it was a pain. I ended up making a pointer/remarking everything over to the pass side