Robert you got it! The oil filler tube is the last main item which the front cover provides mounting.
Also, the front cover provides mounting for the front engine seal, and partial mounting for the oil pan via the front 2 lower studs and nuts. Needless to say, the front engine cover serves many purposes!
Hey! Hey! I finally won something, a cigar, after 58 years! I don't even smoke...
This was definitely a group effort and Russ, Tony and Robert all get a cigar!
So here is a recap of components the front engine cover provides mounting, in addition to serving as the front cover, and providing timing marks:
oil pump, fuel pump, water pump, distributor, oil filter, oil filler tube, front seal, and partially for the oil pan.
Y'all forgot about the fuel filter housing.
Not mounted to front cover, but is mounted to oil filler tube which Robert added. ...and of course oil filler tube also provides mounting for the oil filler tube cap. If we did the “Kevin Bacon” 2nd degree of mounting the list would probably run the into the dozens. Point here was to list those things directly mounted to front cover.
Bottom line was that the front engine cover was the ”Swiss Army Knife” for the 1963/64 engines!
Russ, I thought about that as I was drifting off to sleep last night; wife says I should get a life...