Holley Carbs

Original 1965 Holley

Original 65GT350 carbs would have the part# (3259-1) plus the date 
code, something like: 562, which I believe means: 1965 (5), 6th month (6), 
second week (2). For 1966 the Shelby part#, S2MS-9510-A, was also stamped on 
the airhorn along with the Holley part# and the date code. My original 66 
carb has 3259-1, S2MS-9510-A, and a 622 date code stamped on the airhorn. I 
assume a 66 carry over car would have a 65 type carb without the Shelby part# 
but with a date code but I'm not sure.