PPE did one in a 70 2wd.
Here is their website. They have all the stand alone controllers you will need to make it happen. A google search will bring up a bunch of articles on their pickup as it was in Diesel Power mag and others. Your best bet, and probably the cheapest, would be to find a wrecked duramax to pull the engine/tranny out of so you will have everything there.
EDIT:
Here is the DP mag article.