Smog pump stamping
 

this is a 68 cast date pump with a very early 68 date is the date stamp in the correct place

I have had a few pumps stamped there but most of them are on the small machined area to the right of your stamp.

Also seen a couple where this one is located... 138th day of 68 Nice pump.

this was on a 69 Camaro 1st week of sept of 68 build seem like a early date for that

Early ‘66 pump
 

This Smog pump came off an early ‘66 GTO.

Chris.

My 1969 Van Nuys Z28 09D 1968 build which still has its original smog pump and is stamped 23481S

This is my '67 "06D" GTO pump date which is stamped in the machined area.

Grant,

Your stamp of 1447 looks to be May 24, 1967 which lines up with your car.

way is the last letter differ on these pumps is it a date code or where there where built ?

Yes the last letter is plant build code, I think S = Saginaw MI, Y = Yipsalanti MI, not sure on the Z and U, Maybe someone will add to the post.