1972 Big Block Smog A.I.R. Pump Question

[Monte M.]

Most 1972, 454 cars have what we think of as the normal AIR pump. A few of them had the "1968-style case-mounted pressure relief valve" as the JG states it.

My question to any of you that might have this set-up, does your have the spacer between the pump and the pulley that typically geos on a small block.

I would be interested on the approximate build date of your car as well.

This is another one of those strange things that happened, but not a ton is known about. So, any input would be a huge help.

Thanks for taking a look.

P.S. I have talked to Bill.

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Most 1972, 454 cars have what we think of as the normal AIR pump. A few of them had the "1968-style case-mounted pressure relief valve" as the JG states it.

My question to any of you that might have this set-up, does your have the spacer between the pump and the pulley that typically geos on a small block.

I would be interested on the approximate build date of your car as well.

This is another one of those strange things that happened, but not a ton is known about. So, any input would be a huge help.

Thanks for taking a look.

P.S. I have talked to Bill.

Monte-----


Personally, I really question whether any 1972 Corvettes were originally built with the AIR pump with the integral, 1968-style relief valve. However, if such pumps were installed at St. Louis I would see no reason that they would have been limited to big blocks since the pumps for all engines were the same. If the plant was, for some reason or another, installing that style pump for some period of time it wouldn't have mattered which engine was involved. Functionally, the 1968 style pump could have been used on 1972's, though.

The manufacturing date code on the pump would be important in determining if the pump was originally installed. However, it's possible that a pump could have a "correct" date code for a given car and not be the pump originally installed. That's because GM was manufacturing the 1968 style pump for SERVICE well after 1968. In fact, the 1968 style pump was sold in SERVICE for all 1968-74 Corvette applications for many years. Still, it's unlikely that a "correctly dated" 1968-style pump would find its way by random chance onto a 1972 Corvette (but not so unlikely that someone might have done so on purpose).

As far as the AIR pump pulley spacer goes, I've never seen a big block with the spacer. I do not even understand how the pulley would properly align with the drive pulley for a big block if any of the available spacers were installed.

[Monte M.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
I bought my car twenty five years ago. It came with a bin full of parts. I just took the parts out to see what was in there for sure. There is a 68 style pump with the number "09711W" on it. not only is the pump there, there is the correct dirverter valve, all the correct hoes with part numbers and ribs on them, check valves with the correct numbers, the original exhaust manifolds, and the correct pulley is still mounted to the pump.

Plus the biggest factor for me is that the pump has the date of "097' of 1971. This is approximatly early April.

The Jg states that this happened. The fact that I myself put these parts away twenty five years ago make me think there is a very good chance thay might be correct.

The pulley spacer is not on the pump. It was just with the rest of the stuff. that is why I asked.

I will take a look and seewhat the allignment of these parts works out to be.

This is why I am asking any other owners what they might have seen.

Personally, it is looking pretty good to me. The fact that the date is almost a years earlier than my car was actually built is one factor that is off. Why would someone have put this odd pump, 68 style with 71 date in with a bunch of other 72 parts.

Too many things fit. The JG says it happened. They must have gotten the idea from somewhere.

Thank for checking in.

EDIT: Joe, The JG does say "some 1972 Corvette's". So, you are correct. It was all cars not just big blocks.

Monte

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
I bought my car twenty five years ago. It came with a bin full of parts. I just took the parts out to see what was in there for sure. There is a 68 style pump with the number "09711W" on it. not only is the pump there, there is the correct dirverter valve, all the correct hoes with part numbers and ribs on them, check valves with the correct numbers, the original exhaust manifolds, and the correct pulley is still mounted to the pump.

Plus the biggest factor for me is that the pump has the date of "097' of 1971. This is approximatly early April.

The Jg states that this happened. The fact that I myself put these parts away twenty five years ago make me think there is a very good chance thay might be correct.

The pulley spacer is not on the pump. It was just with the rest of the stuff. that is why I asked.

I will take a look and seewhat the allignment of these parts works out to be.

This is why I am asking any other owners what they might have seen.

Personally, it is looking pretty good to me. The fact that the date is almost a years earlier than my car was actually built is one factor that is off. Why would someone have put this odd pump, 68 style with 71 date in with a bunch of other 72 parts.

Too many things fit. The JG says it happened. They must have gotten the idea from somewhere.

Thank for checking in.

EDIT: Joe, The JG does say "some 1972 Corvette's". So, you are correct. It was all cars not just big blocks.

Monte

Monte-----


Well, it's not impossible that it occurred. The date "discrepancy" adds another doubt, though. However, I suppose it's possible that the plant ran short and some pumps were pulled out of GMSPO inventory (with consequently older dates) to "fill the breech" and keep the line moving. This is just a guess, though, and the big question mark is that GMSPO would likely not have had enough inventory to keep production lines going for very long, especially considering that if the Corvette plant ran out other GM plants would have run out, too (or, they would probably have transferred some inventory from other plants before resorting to GMSPO).

Saginaw Division manufactured these pumps for GM.

[Monte M.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
When I bought the car in the 80's, it had just turned 35,000 miles and was a two owner car. At that time I dd some research of the previous owners because the person I bought the car from told me all the original parts were in the bins except the carb and air cleaner. As time went on I found out the the original owner did not have the air cleaner, but the original carb was on one of his other cars and he refussed to part with it.

If I would hae know then hat I know now about those carbs, I would have pressed a lot more to get it back then.

I found a few other parts that I ended up getting from the original owner. The whole time he kept telling me all the original parts that were taken off the car were in the bins. I glanced in the bins years ago before I put them in storage and saw what looked like all the original parts, but did not spend a ton of time on it as "numbers matching" was not HUGE yet.

My point in running on about this is, the previous owners told me the parts were original.The few things that were not there they told me about.

I have been working on my 63 for the past years and it is time to start doing something with the 72. It took a long time to track down a few of the other parts that were missing. So, when I put this car back together, I am going to put this smog stuff on it and not worry about it.

As we both know, there was some strange stuff done to these cars. Even at the factory. If I ran across a so calleed correct pump for the car, I do not think I would be interested in it.

Thanks for your input though.

take care,

Monte

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
When I bought the car in the 80's, it had just turned 35,000 miles and was a two owner car. At that time I dd some research of the previous owners because the person I bought the car from told me all the original parts were in the bins except the carb and air cleaner. As time went on I found out the the original owner did not have the air cleaner, but the original carb was on one of his other cars and he refussed to part with it.

If I would hae know then hat I know now about those carbs, I would have pressed a lot more to get it back then.

I found a few other parts that I ended up getting from the original owner. The whole time he kept telling me all the original parts that were taken off the car were in the bins. I glanced in the bins years ago before I put them in storage and saw what looked like all the original parts, but did not spend a ton of time on it as "numbers matching" was not HUGE yet.

My point in running on about this is, the previous owners told me the parts were original.The few things that were not there they told me about.

I have been working on my 63 for the past years and it is time to start doing something with the 72. It took a long time to track down a few of the other parts that were missing. So, when I put this car back together, I am going to put this smog stuff on it and not worry about it.

As we both know, there was some strange stuff done to these cars. Even at the factory. If I ran across a so calleed correct pump for the car, I do not think I would be interested in it.

Thanks for your input though.

take care,

Monte

Monte-----

If you believe the pump to be original then by all means install it. While you might lose a few points in judging, it won't be enough to have much effect on the final score.

As far as the pulley spacer goes, you might try to install it, too. However, I bet you'll not be able to get the pump pulley to line up with the drive pulley.

What is the part number of the AIR pump pulley (should be embossed on the front or rear of the pulley) and what is the thickness of the spacer (not including the pilot shaft that inserts into the pulley)?

[Monte M.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
The spacer is 3/4" thick not including the pilot shaft. The pulley number is 3917234 AL. I am guessing the last numberis a 4. It is a little mussed up.

Monte

[Monte M.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
When I got the car i got a set of NOS grills, black door pillar trim, weather stripping, center console (white), licence plate bezel, exhaust bezels, T-top weather stripping, NOS rear bumpers, hood candy, and tons of other nickel dime stuff. Along with all that NOS stuff there are a lot of small packages. a lot of them are rocker balls and studs,but a few I have no idea of what they are.
the part numbers are
3872955 (bushing)
368077 (spring)
3869910 seal)

Do you have any idea what they might be for. there are three or four set of original points and a few other new parts that do not have a part number.
Plus, as I looked further and took the exhaust manifolds out, I realized one of then is dated "78"
Thanks again,
Monte

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
The spacer is 3/4" thick not including the pilot shaft. The pulley number is 3917234 AL. I am guessing the last numberis a 4. It is a little mussed up.

Monte

Monte-----


GM #3927134 is a small block AIR pulley, not a big block pulley.

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
When I got the car i got a set of NOS grills, black door pillar trim, weather stripping, center console (white), licence plate bezel, exhaust bezels, T-top weather stripping, NOS rear bumpers, hood candy, and tons of other nickel dime stuff. Along with all that NOS stuff there are a lot of small packages. a lot of them are rocker balls and studs,but a few I have no idea of what they are.
the part numbers are
3872955 (bushing)
368077 (spring)
3869910 seal)

Do you have any idea what they might be for. there are three or four set of original points and a few other new parts that do not have a part number.
Plus, as I looked further and took the exhaust manifolds out, I realized one of then is dated "78"
Thanks again,
Monte

Monte-----


GM #3872955= rear sway bar link bushing

GM #368077= 1973-76 accelerator pull-back spring

GM #3869910= 66-74 Muncie speedometer fitting seal assembly (goes INSIDE the fitting; not the o-ring on the outside)

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
The spacer is 3/4" thick not including the pilot shaft. The pulley number is 3917234 AL. I am guessing the last numberis a 4. It is a little mussed up.

Monte

Monte-----


A few more questions for you:

1) What is the number STAMPED on the diverter valve? This number will be stamped on the flange of the valve (i.e. where it connects to the pump)

2) What material is the pulley spacer fabricated of (i.e. steel or aluminum)?

3) Is there an elbow between the diverter valve and pump?

[Monte M.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
You are correct. I have a big block pulley here and was looking at that by mistake. When you asked me the pulley number I had to make sure I was giving you the correct number.
If you look at my previous post, I did an "EDIT" where I give you the credit for reminding the pumps are the same for big blocks and small blocks, and determining it was a small block pulley.

There is still the fact that this 68 style pulley has a late 71 date on it making it correct for a 72.

The real reason I intially asked for information about these pulley's was to see what kind of dates were on what vin number cars. With these oddball pumps, was it common for the dates to be a little oddball as well, or did they fit into the timeframes of regular production.

The one person that PMed me has the same pump and it is seven months before his car build date. This is the information I had hoped to gather about these pumps.

I am going to start another thread asking the question in a better and more clear, hoping to get people to give me the information that might make some sence of all this.

The fact the the JG has this in it means that it was common enough to mention. Now, I am just hoping to do a little more research on it.

Thanks again Joe,

Monte

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,
You are correct. I have a big block pulley here and was looking at that by mistake. When you asked me the pulley number I had to make sure I was giving you the correct number.
If you look at my previous post, I did an "EDIT" where I give you the credit for reminding the pumps are the same for big blocks and small blocks, and determining it was a small block pulley.

There is still the fact that this 68 style pulley has a late 71 date on it making it correct for a 72.

The real reason I intially asked for information about these pulley's was to see what kind of dates were on what vin number cars. With these oddball pumps, was it common for the dates to be a little oddball as well, or did they fit into the timeframes of regular production.

The one person that PMed me has the same pump and it is seven months before his car build date. This is the information I had hoped to gather about these pumps.

I am going to start another thread asking the question in a better and more clear, hoping to get people to give me the information that might make some sence of all this.

The fact the the JG has this in it means that it was common enough to mention. Now, I am just hoping to do a little more research on it.

Thanks again Joe,

Monte

Monte-----


Do you mean the pump has a late 1971 date on it? Also, keep in mind that the "1" could mean 1971, 1981, or 1991. That pump was being manufactured for a LOT of years for SERVICE. Can you post photos of it?

[Monte M.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,

The number on the dirverter is 29199.
The spacer is steel, not aluminum.
The elbow looks like the elbow in all the picture I have of 1972, 454 cars. It is pretty simple. It is basically just an off-set. It is very clear the that part is correct.

M

[Joe L.]

Re: 1972 Big Block Smog A.I.R. Pump Question

Joe,

The number on the dirverter is 29199.
The spacer is steel, not aluminum.
The elbow looks like the elbow in all the picture I have of 1972, 454 cars. It is pretty simple. It is basically just an off-set. It is very clear the that part is correct.

M

Monte-----

The "29199" valve is a small block valve. "29190" was the big block valve for 1972.

I'd still be very interested in seeing photos of the pump if you could post them.