I commend you for being creative, but I'll give you a little warning about that overdive unit if yoy hook it up this way. Whatever you do, make absolutly certain to lock out the overdrive befroe you try to use reverse. If you try to reverse with the od freewheel clutch engaaged, you'll destroy the unit. On the original trans, there's a lockout pin that prevents this by disengaging the od when the trans is in reverse.
When you get it together, post some pix. The project sounds intersting.
You also mentioned the Columbia in an earlier post. I didn't see a responce, so I'll tell you what I know about it. The Columbia, or at least the ones I've seen, install in the rear diff, not the trans. I seem to recall that it actually replaces one of the axle bell on the ford housing. It works somewhat like the planetary 2 speed axles on big truck, just with an overdrive ratio instead of a low gear. If I can find more, I'll post it.
