rushlow, don't take comments to heart, everyone is just trying to help.
I am betting that it has a build date thats late 68, usually anything past Oct back then was the next model year.
The front end is from a 69 through 70 model, and they didn't use the term 5.0 liter back then.
V8's available then were 283, 307, 327, 350 started in 69 and a 396 big block.
Here is a link that will help you a little.
http://www.pickuptrucks.com/html/his..._segment8.html
Hope that helps.
Randy