Flip top cap on a dart

Glenn Radford said
I'd sure like to put one of these flip caps on my 73 Swinger, but I need to know which cap fits, even if I have to make my own adaptor. Could someone please answer that question?
I don't want to buy the wrong one....

As far as the mechanical layout is concerned I don't know if there's a difference. In appearance, yes. But I think they all fit the same. And if you have to make it fit anyway, I'd go with the one you like best and make it happen.

I saved the one that was on my '68 Barracuda and welded the sheet metal pocket into the quarter on my '72 Duster. Lower profile and I think it'll work out fine.