[ZeGermanHam]

Roger, I recently ordered that 4x10" RetroSound speaker for the dash of my '66. If you're curious, the real-life bottom mount depth of it is about 2-1/32". That's a little less than the published numbers, which is a good thing.

I know it's apples to oranges, but the factory original 4x10" speaker that I removed from my '66 with A/C measured at about 2", so the RetroSound speaker should work for me. Hope it does for you as well. Like you, I am pairing it with two 6x9" speakers - Alpine R-S69.2 R-Series in my case. I have bench tested all of my speakers, and the RetroSound 4x10" will be great for providing front fill when used in conjunction with other speakers. It gets plenty loud, is nice and clear, and I think you will like it. It doesn't have much in the way of bass, but that's what the 6x9s are for. You will get better sound quality out of this speaker than you would have with the previous one that didn't fit, too, so I'd consider it a happy accident.