I've seen the pictures of the rally car and everything, but what I need to know is what model and year car was used for the parts to do the conversion? was it a 929 or a 626?

TIA

 

This exact topic was covered about a week ago. Please do a search.

According to the current owner of the car, most of the parts for 4WD were custom.

 

Ok I read the thread, but I decided that instead of using already existing parts, why not try something like this:

Have a sort of transfer case fabricated, have it to that it mounts around the driveshaft, which has been equipped with a gear that fits into the transfer case, which has a gear that's on another drive shaft that goes up front.

Could I use a rear diff from another 1st gen just turned backwards? Or would it make the wheels move backwards too?

Here's a pic, red is the fabricated/unstock parts.

 

well you have to use a diff from an IS(independent suspension) so you can actually keep your from suspension setup. But doing it your way is basically impossible.
The only way other than making a new front-end is to adopt a FWD suspension and steering setup from another car.

 

Please search. I started this discussion a few weeks ago and there's much more info there.