[LS short box]

Not a truck swap but on my 73 LS3 swap I used "stock" style aluminum radiator. I struggled to find upper hose that fit. I ended up using two hoses and a splice. The splice also had a NPT opening for the head vent line.
I got splice from "Jaguars that run".
Lower hose I got from Oreillys by looking thru the selection in the back room.
Pic of the 73 upper hose.