'71 smog components NOS or GM replacement ???

[George W.]

Hello all . I have a '71 LT1 smog system I purchased from a Chevrolet dealer in Novato , Ca. back in 1988 . What are the chanches of this stuff being correctly numbered and dated for a '71 Vette ? The milled area on the pump (aluminum) has 129881 stamped . The back of the pump (cast iron) has 7817872 cast with 8263 cast under that number and upside down . I have several new diverter valves as I recall that the counterman could not get a good crossover reference , so he gave me 4 of these (charged me for one) . Are there numbers on these ? Let me know what you know , and if I need to get more info . Thanks , George

[Joe L.]

Re: '71 smog components NOS or GM replacement ???

George-----

The chances are near zero that the pump that you were sold is correct. The correct configuration 69-71 AIR pump was discontinued and replaced, for SERVICE, by the 1968 style pump more than 30 years ago. If the pump is in a box, what is the part number of it. Otherwise, if you post a picture, I might be able to ID it. For a picture, make sure to include the "flat" surface on the upper portion of the pump's aluminum housing.

As far as the diverter valves go, there is usually a number on them. For all metal valves, the 5 digit ID number is STAMPED on the bottom of the flange that attaches to the AIR pump or elbow. If you provide the number, I might be able to ID the valve for you.

The plastic/metal valves have the complete part number stamped on the large metal "hat". Plastic/metal valves are SERVICE-only with respect to a 1971 Corvette; this type valve was never used in PRODUCTION for that model year.

[George W.]

Re: '71 smog components NOS or GM replacement ???

Hi Joe . Thanks for your response . If I can figure haw to post a pic or two , I will . I may just send to your e address if that is ok ? Two of the valves are the replacement type you described . The other two are all metal . The number on one flange is : 29295 : the other is 24766 . Back to the pump , is the 129881 number , stamped onto the milled portion of the aluminum bolt bossing ,a date code ? I have all the reciepts for these , but as you may know , some counter guys took hand writing lessons from doctors .lol. The one number I think might be for the pump is : 6415631 ?? Thanks again , and I'll try to send some pics

[George W.]

Re: '71 smog components NOS or GM replacement ???

Let's see if the photos show up . Ths could be fun .

[George W.]

(Message Deleted by Poster)

Message Deleted by Poster

[George W.]

Re:can anyone tell me why this is not working?

I've found a host for my photos and added the url to my post , but the icon comes up "broken" . I have sent this to another e mail address , and it works there . Is there something else I need to know , do ? Thanks ,George

[Joe L.]

Re: '71 smog components NOS or GM replacement ???

George----

I'm afraid that I can't ID the "29295" and "24766" valve ID numbers. They may be truck pieces. I can't find any passenger car applications for them.

The number on the machined area of the pump's aluminum housing is a date code.

The "6415631" is not the part number for any AIR pump assembly that I can find.

I may be able to tell you more when I see photos of the pieces.

[George W.]

Re: '71 smog components NOS or GM replacement ???

Thanks Joe . I got your e mail , and your info helped a lot . How does on decipher the date codes ? Geo

[Joe L.]

Re: '71 smog components NOS or GM replacement ???

George-----

The date coding system that I'm familiar with has the first 3 characters as the Julian date code and the fourth character is the last digit of the year. If so, then this pump was manufactured the 129th day of 1978 or 1988. The part that confuses me here is that the fifth character usually denotes the shift that it was produced on and the sixth character identifies the pump model. The latter is usually an alpha-character, In this case, your fifth character is an "8" which is not possible for a shift designator and the sixth character is a "1" which I've never seen for a pump model. I'm going to surmise that there was some change in the coding and what this decodes to is the 129th day of 1988 and first shift.