I'm thinking that when the open knuckle D44 came into use it was shared into the later years of the 73-87 trucks and maybe a bit later til IFS (inferior front suspension
) came about.
The 88-91 Blazers and Subs I think were the same body style. No doubt Dodge used the same (I think).
Not to mention the D44 was used by other manufacturers. Grab a few phone pics, a few measurements, and head for the scrapyard