They are the same width. The 64.5 top has a different setup for the tensioner cables and had stronger brackets. In 67 they started a slotted deal on the second bow from the front. This allows raising it get a more prounced peak. The early tops differed, also, in the tacking on the ends of the 2nd and 3rd bow. The tops are interchangeable. I had a 68 cv with bad bows. Answered an ad for 64.5 top in NY For 135, guy sends me mint bows. It fit perfectly on the 68. Over the doors there is an adjustment screw to help the sagging issue. It differs on the 68 (maybe 67 too) top over the preceeding ones.