Found them. Had to search grote 2 to 3 wire adapter. No idea if this site is legit but here they are. Buddy that gave me mine said any truck/trailer shop “should” have them.The part# on that Grote adapter didn't turn up in a search, but I found these that should do the same thing.
https://www.amazon.com/Custom-LED-Blinker-Genie-Automobiles/dp/B07DQRPRLW
What size is the radiator core? I have a nice blank aluminum shroud from my buggy build that I didn't use because I needed a deeper one for the Volvo fan. I think it's for a 22x19 radiator.
One of these days I'll get around to welding it up.