On a '66 Olds Tri Carb manifold, there is a pad that appears to show a date code. Mine looks like a 151. what does that mean? Is that the 151st day of the year? The casting number appears to be 393238. There is also a large letter "F" cast on one of the runners and the letters "AZ" cast in the front of the manifold

Were there different castings of this manifold, or was there only one version? I have a correct set of carbs (Rochester casting number 7032575 center & 7029683 ends), but would like to know more before rebuilding them.

 

Anyone familiar with Old's date coding on castings?

 

Anyone?

 

Found info on another site. Old's casting dates are all three digit numbers which are "Julian Dates." These numbers designated the day of the year the casting was made (001-365).