68 Z28 Smog Pump Pulley

[1968 Z28]

Question for all the experts.....I have an original 68 Z28 (engine build date of June 19, 1968) that has a smog system that has never been touched, although it has been sitting on a shelf for the last 25 years.  Now that I have decided to restore the car back to original, I have been cleaning up the smog system to reinstall it.  I had always thought and seen nearly everywhere that the 68 Z28 smog pump was supposed to have the deep groove #3925522 pulley, but mine has the #3927116 pulley.  I looked up the setup in the 68 Assembly Manual and under the RPO Z28 section nothing is mentioned about having a different pulley other than what comes standard on all the other V8's with manual transmission and no air conditioner, which is the #3927116 pulley.  I looked up the parts manual and it stated the #3925522 pulley was for the 68 396/427 HI Po engines but nothing was mentioned about the 68 302 having anything different other than the #3927116 pulley.  Am I missing something here?  Could someone possibly tell me why this discrepancy is present in my system or is it actually standard for the #3927116 to be present?

Thanks in advance for any info.......
Sonet

[CVKUEBER]

According to the chev parts and acc catalog printed in 1983. The 3927116 is for all small block with m/t w/o a/c.

[1968 Z28]

Yeah Coy....I looked it up in a 1976 and 1981 parts manual and that is exactly what I saw.  Thanks for the info.
Sonet

[1968RSZ28]

The CRG '68 Camaro pulley chart list the 3925522 deep groove smog pump pulley for 1968 Z/28, L78, and L89 engines...

http://www.camaros.org/pdf/pulleys-68-2007-02-01.pdf

Paul

[1968 Z28]

Yeah.....I looked at that pulley chart and I also read Jerry's book and they both state that it should be a #3925522 pulley but like I said.....this system has never been touched so I'm fairly sure that it came from the factory that way.  I guess I will just leave it the way it came.  Thanks,
Sonet

[1968RSZ28]

Maybe the smog pump and pulley were replaced as an assembly.  What's the date code on the smog pump you have?

Paul

[1968 Z28]

17481Y

[KurtS]

I've seen another 68 Z with an original 116 pulley. It should have the 522, but it doesn't....

[CVKUEBER]

The SERVICE replacement number shown in the GM parts catalog is 3927116. It's possible it may have had the other pulley originally. It could have been in a crash, or possibley replaced because of a service bulletin ect.

[1968 Z28]

Yeah I guess that could be possible.  I bought the car in 1972 from the original owner.  I talked with him and asked about parts replaced, collision, or any other work.  He said the the car had never been in a collision and the only parts that had been replaced was the muffler and tail pipes.  Of course that does not mean he told me everything he knew about the car....HA.  But it does look original.  The date on the smog pump puts it's manufacture around late May of 68 so that should be about right for an original pump.  Like I said, I think I will just leave it as it is.....Especially since I saw an original 3925522 pulley for sale on eBay for $950.00.  Whoa!!!!

Thanks again,
Sonet

[1968RSZ28]

Especially since I saw an original 3925522 pulley for sale on eBay for $950.00.  Whoa!!!!

It's $975.00 + shipping!...     

http://cgi.ebay.com/ebaymotors/1968-72-3925522-SMOG-PUMP-PULLEY-CORVETTE-427-454-L88_W0QQitemZ180215540706QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?_trksid=p4506.m20.l1116

Paul

[1968 Z28]

Paul....You're so right....that's the one!
Sonet

[Jerry@CHP]

My white survivor 68 Z28 has the 522, most original cars that I've inspected and know they have not been tampered with have had the 522 pulley.  That's not to say that a 116 could have been used because of a supply problem.  Stranger things have happened.  The belt will not stay on if you take it up to 6500 rpm, I know that.

Jerry

[1968 Z28]

My white survivor 68 Z28 has the 522, most original cars that I've inspected and know they have not been tampered with have had the 522 pulley.  That's not to say that a 116 could have been used because of a supply problem.  Stranger things have happened.  The belt will not stay on if you take it up to 6500 rpm, I know that.

Jerry

Jerry.....do you still have the 3925522 NOS pulley for sale?  I noticed on your web site in the NOS and Rare Parts section that it was mentioned as being in stock.  Might be interested in getting one from you.  I also have noticed that Classic Industries is showing a reproduction for sale and it looks like the original.....Have you seen this one?  Thought maybe I might check this one out if you don't have any for sale anymore.

Thanks again,
Sonet

[Charley]

I would leave it alone. I used to get flack over what many told me was the wrong redline tach in a 67 Z I had but it had been there forever so I left it that way. Now I think there is a large cross section of others that also came that way. Makes for nice conversation also....