68/68 AIR Question

[Rich G.]

I was at a local Cruise Night and a gentleman was looking over my 68 L71. He said “I see you have a smog pump.” I told him I thought all 68 and 69 did. He said he was the original owner of a 69 400 car that did not have one when he bought it in NY.

I never like to get into an argument over theses things so I went and looked at his car, which had no AIR and no evidence of it on the exhaust manifolds. Obviously 49 years is a long time and he said he had had the engine rebuilt but he did not seem like somebody whose memory was suspect. He also wasn’t an NCRS type who would own aTM/JG or care about originality.

I always think about my old boss who when confronted with a seemingly impossible or obviously incorrect statement would shrug his shoulders and say: “Maybe he knows something we don’t know.”

Seems not likely to me. You?

Rich.

[Richard T.]

Re: 68/68 AIR Question

Seems very unlikely but who knows? My brother and I both bought new 69 s at Malcom Konner in Paramus New Jersey , one big block and the other small block. Both had A.I.R. I understood it to be mandatory equipment except for the L-88. All the magazines back then had articles that toted the benefits of removing the system. It was the first thing that was done at Motion Performance (New York) when they modified these cars.

[Rich G.]

[Terry B.]

Re: 68/68 AIR Question

The 68/69 TJM states that all 68 and 69 Corvettes had the AIR system. Did you happen to look for the plugs in the exhaust manifolds of the '69?

Terry

[Rich G.]

[Joe L.]

Re: 68/68 AIR Question

I was at a local Cruise Night and a gentleman was looking over my 68 L71. He said “I see you have a smog pump.” I told him I thought all 68 and 69 did. He said he was the original owner of a 69 400 car that did not have one when he bought it in NY.

I never like to get into an argument over theses things so I went and looked at his car, which had no AIR and no evidence of it on the exhaust manifolds. Obviously 49 years is a long time and he said he had had the engine rebuilt but he did not seem like somebody whose memory was suspect. He also wasn’t an NCRS type who would own aTM/JG or care about originality.

I always think about my old boss who when confronted with a seemingly impossible or obviously incorrect statement would shrug his shoulders and say: “Maybe he knows something we don’t know.”

Seems not likely to me. You?

Rich.

Rich------

These "allegations" regarding 1968-69 cars seem to come up all the time. I don't think that ANY 1968-69 Corvettes were built without AIR. By "69 400 car" do you mean a car with THM-400 or L-68?

[Joe L.]

Re: 68/68 AIR Question

Seems very unlikely but who knows? My brother and I both bought new 69 s at Malcom Konner in Paramus New Jersey , one big block and the other small block. Both had A.I.R. I understood it to be mandatory equipment except for the L-88. All the magazines back then had articles that toted the benefits of removing the system. It was the first thing that was done at Motion Performance (New York) when they modified these cars.

Richard------


Even 1968-69 L-88's were originally equipped with AIR. 1969 ZL-1's, too.

[Terry M.]

Re: 68/68 AIR Question

I have told at least half a dozen judging manual revision teams to beware of original owners. We miss-remember things frequently. I can say that from personal experience.

The other, less wise a$$ answer, is that we judge and write the manuals to Typical Factory Production (TFP) standards. If a 1968 or 1969 Corvette was built without AIR equipment it was not TFP. That includes L88s by the way.

[Rich G.]

[Joe L.]

Re: 68/68 AIR Question

Joe

I meant L68. Sorry I wasn’t clear. if I see him again I’ll be sure to have my TM/JG handy. He seemed interested to know why he didnt have AIR even though he thought it was always that way.

I can feel for him, as the older I get I can remember things whether they happened, or not. :-)

Rich

Rich-----


For 1968-69 (as well as later), exhaust emission control was a federal requirement. I cannot see GM building any cars that lacked it. The fact that it was installed on L-88's and ZL-1 underscores that. Of course, there are different ways of achieving exhaust emission control. As a matter of fact, GM did use one of the other methods known as the Controlled Combustion System (CCS) on most other 1968-69 Chevrolets with automatic transmission. Such a system was initially scheduled for use on Corvettes but was never actually used for any 1968-69 Corvette. The CCS system used specially calibrated carburetors and distributors as well as other mods to achieve exhaust emission control. So, if CCS was used on 1968-69 Corvettes, there would also have to have been different carburetors, distributors, and other parts than were used on AIR equipped Corvettes. However, no such carburetors, distributors, and other parts exist. So, how could any 1968-69 Corvette, especially a 3X2 application using carburetors which were unique to Corvettes, have been equipped with CCS, the only alternative at the time to AIR for the required exhaust emission control?

I would inspect the car you mentioned carefully to see if there is any vestige of a once-installed AIR system. If the exhaust manifolds do not have plugs, then that means that when the AIR system was removed, the manifolds were also changed. Surely, the owner, if he actually is the original owner, would recall that. Carefully inspect the area where the AIR pump bracket would have bee installed for signs of its once presence. Also, check the waterpump pulley. 1968-69 Corvette big blocks used a 3 groove pulley with the outer groove for the AIR pump driver. I highly doubt that GM would have built a 68-69 Corvette with an unused pulley groove.Instead, they would have used the 2 groove GM #3889372 pulley which was in their "parts bin" and used for earlier and later big block applications without AIR.

So, why didn't GM use the CCS system on 1968-69 Corvettes as they did for most 1970-71 Corvettes and as they did for most other 1968-69 Chevrolets with automatic transmission. Certainly, there was a significant cost savings using CCS rather than AIR. I believe that the reason was that the CCS system was more performance-robbing and, at least for the 1968-69 period, they wanted to preserve the better performance allowed by the AIR system, even at considerable additional cost. For 1970-71, they "weakened" on this. However, one must note that for 1970-71 they did keep the AIR system for the 2 SHP engines available, the LT-1 and LS-6. I believe that was because they wanted to keep these engines free of the performance-robbing effect of CCS-calibrated engine components and systems. For a performance engine of the day, AIR was, by far, the best type of exhaust emission control, notwithstanding the opinions of neophytes.