Check out this link on the history of Chevy Trucks by Don Bunn
http://www.chevytrucks.org/resources/history_of_chevy_trucks.htm 1947 – 1955.5 Advanced Design Series (AD)
1955.5 – 1959 Task Force Series (TF)
Then Bunn tells us, “Model Series designations for 1960 were completely revised. The new system began with a letter prefix. For example, a "C" prefix indicated a conventional cab; a "K" indicated a 4 wheel drive model; a "P" model was forward control; an "L" was a low cab forward; an "S" was a school bus and an "M" was a tandem.”
It is a really nice and informative article.
K
