They are getting harder to find. I was in a pinch a few years ago and was able to get one from the Napa down here in Colorado Springs, they still show having them in stock but they are pricy. Also you could check these guys out:
On another note used these guys to do a 4x4x2 box for me in the past: https://ravenpowersteeringspecialist.business.site/ We actually used them for rebuilding all the old Scout boxes when I was working at a shop in the Springs.
1969 Bronco: Full widths, 3 linked front end, 37's, hydro-boost, 4x4x2 box, ZF5, Atlas t-case, and fuel injected 302