66 coupe. These work great and have plenty of backspace for regular 6.5 inch speakers. Used Polk Audio DXI 650s speakers. These have 2 inch mounting depth and they fit (but not a lot of room left). I did not need to buy special low profile speakers or cut any metal to make them fit. 4 stars because I had to trim a little and add a speaker mount to get them to fit right. Read below. But, I'm very happy with them. And the cutout for the screw that holds the door sill plate on is in the exact right spot.
The reason for only a 4 star rating is because I had to trim them a little to get them to fit perfect. The lip at the bottom had to be trimmed off so they would fit under the door sill plate. But the sill plate holds them on just fine. I also trimmed the the lip at the top where they meet the windlace strip just to make it fit a little nicer. (could have cut the strip short instead). Lastly on the driver side, I trimmed down the tab that holds it close under the dash. It was so tight it was warping