Great pics of the glove box holes!! Thanks!

Any chance we could get some measurements while you've got it out?

The crossover box is required with all 3 speaker dashes. The same crossover box is used on cars with two rear speakers.

On your stereo two rear speakers were an extra option. I'm not sure if it would be coded on the fender tag. If I remember right, the 1970 rear speaker code is R31. AM radios with that code got one rear speaker, and stereo radios got two rear speakers. In 71 the code for two rear speakers was changed to R32.

If you have rear speakers the fader switch is different depending on if you have a standard dash or a rally dash. Standard dash speaker fader was up by the gauges. Rallye dash speaker fader was down by the heater controls. AM radio cars use a fader with one pot for a single rear speaker. Stereo radio cars use a fader with two pots for two rear speakers.

Tav