Here is a better picture of my head casting numbers;
http://s1142.photobucket.com/user/52_Ton/library/?sort=3&page=1

On the right is F 27 2- date code July 27 1952

Could the GM 9 be plant #9 maybe??

Mark

1952 GMC 9430 one ton pickup, a work in progress

1952 1-ton pictures on Photobucket