Smog Pump Date Code
 

This is the smog pump from my 73 Z28. No idea if it's original or not. The stamping reads 10231S....the 3 is barely visible, but it's there. Anyone have a clue what the stamping deciphers to?

102nd day of 1973. Thursday, April 12th. Does that fit with your car?....Joe

Is the smog pump installed at engine assembly or at Norwood? My engine was assembled February 20th, Trim Tag assembly date is 1st week of April. Not sure that Trim Tag date reflects actual production, because I'm confident that the rear axle is still original to the car and it's also dated April 12.

The pump was installed at the vehicle assm plant. The Fisher Body tag reflects a projected date. A NCRS page would tell you the actual assm date of the vehicle. From what you've posted, I would think the pump was original to the car.....Joe

Thanks very much, Joe. Based on that info, I would tend to agree with you that it's original to the car. Per all the original paperwork I have for the car, the OO special ordered it in January of 73 and took delivery late in May of 73.

I didn't think the NCRS records went into 1973 :dunno:

I didn't think the NCRS records went into 1973
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You're right. I didn't see that....Joe

FWIW....Using interpolation based on production records from the Nasty Z28 site, my car should have been produced on or about April 19th.

Alwas thought the"1S" suffix meant Chevrolet?
Pic 1 is Jan 24 1969
Pic 2 is 46th day of 1972

Could be. Obviously both of yours have that, mine has it, and one that was just sold on this site also has it. Thanks for the pics, Dave :biggthumpup:

Date code breakdown
 

Per CRG: