I know the 67-9's are wider than the early cars. Best to get the right piece instead of trying to make the wrong piece fit.Don't think so I had to find one from a 64-66. Think the drop part might work though ask Rick at laysons.
This is my '66 Barracuda with the spare tire well from a '68 Valiant. I only used the tire well, not the entire floor. Fuel tank fits without issue.
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View attachment 1715237172