Got another build going. I was waiting until I was mostly done with this one before I started a build thread on it. I'm notorious for picking up trucks and messing around with them for a little while then getting rid of them.
I picked up a '79 K20 on July 4th. Saw it pop up for $700 on Facebook Marketplace. I left with the truck for $540 and drove it home from Aurora, CO to Colorado Springs, CO without issue.
It has a 350/SM465/NP205, D44/14BFF.
I've put at least 500 miles on it in the past month and the only issue I've had is a little coolant leak from what I think is the lower rad hose, looks like it's too big and the 465 has a nice little leak.