Double tab gas caps?
A-body gas caps don't interchange across the lines formed by these groups:
• '60-'66: Unvented cap. Single set of tabs on small-diameter/shallow hub
• '67-'70 (except '70 California): Unvented cap. Single set of tabs on slightly larger/deeper hub
• '70 California + early '71 50-state/Canada: Pressure-vacuum type cap, single set of tabs on larger hub
• Late '71-'76: Pressure-vacuum type cap, two sets of tabs on larger hub.
Find pressure-vacuum cap info in
this article.