75-78 used a tall valve cover with push in oil cap
79-80 used a tall valve cover with threaded oil cap
1980, and maybe 1979, had 2F embossed in front top of valve cover
1981+ valve cover was shorter and does not work with the earlier F valve train
I don't have a concern with the push in oil cap, there are many, many of them still out there running around the world without issues.
the F and 2F engines breath nicely and don't have preasure build up from inside
$40 bucks for the valve cover, was a good deal, half price or better