Here's everything I have in my notes on bed wood for the GMC. I think Chevy was the same back there, but I can't guarantee.
These beds had oak or yellow pine beds made from boards that were cut with dadoes and a shallow rabbit. They were 8 foot and 1 inch long and 3/4 inch thick (1" lumber).
Some pictures attached should show you how they fit and get cut.
There's a writeup about dimensions here:
http://6066gmcclub.com/forum/showthr...1831#post51831
A (2005) study of bed wood coatings found this to be the best for long lasting results out of 10 options:
Three coats of POR-15 Rust Preventative Paint as a seal coat and three coats of Behr gloss black enamel. This finish is on an oak sample and it has no failure at this time. The finish has possibly dulled slightly, but is still very glossy and sealed well. If you plan to paint your bedwood, this finish system should be considered as it is very durable and easy to apply.
As far as I know there's no good video or writeups. If you do it, you could take a ton of pics and post it up!