Stumbled upon this on another site and felt the need to share. It appears that 2006 Honda Civic coupe door weatherstrip works great on our 1964-1966 trucks. It pushes right on and fits without any modifications, per Rob Fisher here: http://67-72chevytrucks.com/vboard/showthread.php?t=617703

Hondapartscheap.com

They are called Front Door Opening Seals and described as Graphite Black.
Brand new in genuine Honda packaging was $38.92 per side.

P/N 72315-SVA-A01ZA, right side.
P/N 72355-SVA-A01ZA, left side.

Probably could get a good used set at the salvage yard for a 20 dollar bill.

In the Stovebolt Gallery ~~ "The Orange Crate" 1965 C10 SWB Step Side Build Thread

Inspired to be different. Different in a way of my own, not in a way that others strive.