Part number help?

[red caddy]

Hi all, I'm currently up grading my '86 1 ton from a 3 row to a 4 row radiator. As I'm sure you guys already know, this is a drop in, BUT the rubbers and top hold down brackets must be changed. I found the rubbers at the local Chevy dealer, but I can't find a source or a part number for the hold down brackets. (it's around an inch longer than the 2/3 row bracket) AFAIK this bracket came stock on most BBC installations with the HD or towing package. Most were 2 piece but I've seen a one piece on a '79-80 C-20 I think (The local chevy parts guy says he's too busy to mess with it and won't let me at the data base, imagine that...) It should still be a "pad order" item, but I've come up empty with all my local sources/suspects and yard dogs. Can anybody out there help me ? Thanks, Paul.