C3 1968 427/390

[Jay L. Flinders]

Need help again does anyone know how to break the date code for smog pumps i.e. 10081Y? Is there a casting number on the smog pumps?

[Terry M.]

Re: C3 1968 427/390

10081Y = 100th day or some year ending in 8 (probably 1968 in your case), 1 is either shift or assembly line (but it doesn't matter which it is), Y = the model of the pump. I believe this is a pump with the external relief valve. the later style -- with the relief valve as part of the diverter valve is the S model.
[Commercial on] FWIW Jay I believe this information and a whole lot more is in the 1968-1968 TIM&JG (Technical Information Manual and Judging Guide) available from the folks who support this board. Click on the NCRS Store radio button at the top of this page. [Commercial off]

[Joe L.]

Re: C3 1968 427/390

Terry and Jay-----

"Y" is, indeed, the model number for the AIR pump with the external pressure relief valve. The "Y" model pump was used for all 1968 Chevrolets, including Corvettes, with AIR. After 1968, it was used ONLY for 1969 L-88/ZL-1. It was also used as a later SERVICE pump for 69-71 applications. A "Y" model pump can be used on any 1968-75 Corvette as a SERVICE item. However, the "S" model 1969-75 pump cannot be used for a 1968 model.

[Jay L. Flinders]

Re: C3 1968 427/390

Thanks Terry amd Joe. Terry I have ordered the reference you suggested.