69, the only thing I would add about the actuator you've got is that it's a linear unit utilizing a screw to transmit the motor's work. It's designed to stop at the end of it's total travel at either end. Perhaps the company that manufactured it can shed some light on alternatives since they would be the logical ones to have been presented with the opportunity to deal with the issues involved.

The unit that Dan mentioned is real slick. It uses a stepping motor (step motor) as an actuator, and has a pretty sophisticated logic board to control neutral start, park, reverse lock out, etc. Then uses small indicator lights to designate gear selection. Even if you do your own setup you could do something similar with switches at the shift mechanism connected to lights on the dash, or whatever, and avoid the clunky OEM type of piece. If you're interested in how stepping motors work and are controlled here's a link http://www.cs.uiowa.edu/~jones/step/

Those factory type floor shift units, as well as the aftermarket ones, utilize detent balls to indicate the stopping points for each gear. You might want to think about using a cable shift mechanism. You could mount the "handle" just about anywhere, perhaps under the seat, just sticking out enough to grab. You can get cables lots of places, but a local marine supply house probably has the ability to make one for you to any length you specify. They probably have some other associated components that would ease design of the hookup pieces too.

Streets, see, your distaste for Mopars is gonna bite ya here!!!! Their units were actually a bundle of cables from the quadrant to the trans. I think you're right about the Edsel, but then they only did it the one year ('58).

Keep up the creative thinking 69. BTW, where's all the help from the self annointed "real" hot rodders?