Need help title decoding

[skippyf15]

I have a 1984 GMC, I started decoding the Vin number but something isn't adding up. I have "GTDC" then 14H which is 1=half ton, 4= two door, H=305 4bbl then 6, year manufactured, location built, then number built. Any ideas what "GTDC" stands for. I bought my girlfriends dads truck and he I've been told ordered this truck. I'm now the second owner.

[zieg85]

http://www.73-87chevytrucks.com/VIN2.htm  should clear it up... GT is GMC, D is your braking system, and C is 1981-86 2 wheel drive

[skippyf15]

Thanks for the help.