For specifics on the lowers, here's what we used on our '75 D100 recently:

From RockAuto they were Dorman part nos: 520335 (520-335) and 520336 (520-336) - still available for about $78 each.

As mentioned in other threads you have to: remove the steering arm bump stop, drill for the strut rod, enlarge the bushing bolt hole in the frame, and remove some material around the bushing flange.