Is that the correct oil cap? I honestly didn't know I had two of them one came off my slant 6 it has long neck with a small snap fit cap. And I have that one. It fits so I was gonna use it. I have several of the turn in style for the later years but I dont have the later valve covers. I'm not sure what I did with the original valve covers off this 360 I cant find them. I have the set of 340 ones that I'm using and a set of 318 ones that came off the truck engine I wont use those they are dented up pretty good. They will be my head painting covers lol