The VIN is laid out as followed Example CCY128Z100327 C=division C=chassis type Y=engine description 1=series 4=body type 8=year Z=assembly plant 100327 build sequence number327th unit produced, certain Flint models start with 100000.
C= Chevrolet
T=GMC
C= 2wd
k=4wd
Y= engine displ. 305 350 454 etc
1= series 10 20 30 gmc 15 25 35 1/2 ton 3/4 ton 1 ton
4 body type pickup
8= year 3 1973 4 1974 9 1979 so-on
Z=plant A=Lakewood B=Baltimore F=Flint J=Janesville S= St.Louis V=Pontiac T=Terrytown Z=Fremont 1=Oshawa 5=London, Canada 8=Shreveport hope this heps