The square body Dodge trucks use a Saginaw steering box. The truck boxes, GM and Dodge, mount on the outside of the frame. (The GM car boxes mount on the inside of the frame, so car and truck boxes will not swap.) The GM and Dodge truck boxes look similar, but I've never taken any measurements for a more precise comparison.

I would guess this steering box was used from back in the 1960's up till at least 87 in the GM trucks. I looked at a mid 1990's 4x4 Chevy and the steering box in it looked different. The 2 wheel drive Chevy trucks may have continued to use the older style steering box into the 1990's though. I'm fairly certain the 2 wheel drive trucks use a very different front suspension from the 4x4 GM trucks in that era. Chevy 2 wheel drive and 4x4 trucks both had independent front suspensions, but very few parts will swap.

VL21, you are thinking of the reverse rotation steering box used on the 4x4's in the mid to late 1970's. It looks the same and will bolt in, but it's NOT the right part!!

Thanks for mentioning the Chevy trucks may have had a faster ratio box. I will do some more salvage yard "research".