just take a spare set of manual regulators and remove the crank part (careful with the darned spring) make a template of the 3 bolt holes for the window motor, I've used any year motor that has a gear and not the cable, from 62 to 99 so far car or truck the gear is the same as the power window gear. temp tack weld it on and check that it'll clear the innards and the glass. BUT the rear windows on the convertible 66's are a *****, I had to re-engineer then by actually turning the motors from the inside to the outside and cut some sheet metal , so not a real clean install. But they work and can be done(TIGHT)