Smog AIR system question
Drifting
Joined: Jun 2003
Posts: 1,455
Likes: 5
From: Upstate South Carolina
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
When Chevy engines had compression ratio lowered ('71-'72), the AIR pump was not needed to make EPA limits on the base SB engine...except in CA. I can't say (for sure) that the '73 & '74 base engines did not have smog pumps in the other 49 states, but I think that is the case. Catalytic converters were added in '75 so AIR system was no longer needed.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
When Chevy engines had compression ratio lowered ('71-'72), the AIR pump was not needed to make EPA limits on the base SB engine...except in CA. I can't say (for sure) that the '73 & '74 base engines did not have smog pumps in the other 49 states, but I think that is the case. Catalytic converters were added in '75 so AIR system was no longer needed.
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Michael S. Palmer
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Solid LT1..
You may be a "wealth of information", but you are the one who's in error. In the 49 states [with the possible exception of the LS5 in CA], the L48 and LS5 engines (auto or manual) did not have the A.I.R. system in 1971 or 1972. I have a CA '71 w/L48 and it did not come with the A.I.R. system either. {And, no, it was not removed..the exhaust manifolds are date-correct and do not have any holes in them.} The LT1 and LS6 engines did have it [for all 50 states]. I stated that I was unsure about the '73 & '74 cars; someone with a '73/'74 A.I.M. can tell us for certain.
You obviously don't have a '71 A.I.M. to steer you straight. Your confidence may be high...but your accuracy is lacking.
You may be a "wealth of information", but you are the one who's in error. In the 49 states [with the possible exception of the LS5 in CA], the L48 and LS5 engines (auto or manual) did not have the A.I.R. system in 1971 or 1972. I have a CA '71 w/L48 and it did not come with the A.I.R. system either. {And, no, it was not removed..the exhaust manifolds are date-correct and do not have any holes in them.} The LT1 and LS6 engines did have it [for all 50 states]. I stated that I was unsure about the '73 & '74 cars; someone with a '73/'74 A.I.M. can tell us for certain.
You obviously don't have a '71 A.I.M. to steer you straight. Your confidence may be high...but your accuracy is lacking.
Melting Slicks
Joined: Nov 2004
Posts: 2,672
Likes: 6
From: Nevada City California
7T1vette,
Actually your statement was also incorrect. 1972 LS-5 optioned Corvettes were indeed equipped with the Air Injection Reactor emissions system. It was 1970 & '71 LS-5's that did not use this system, but used alternative emissions controlled devices.
Actually your statement was also incorrect. 1972 LS-5 optioned Corvettes were indeed equipped with the Air Injection Reactor emissions system. It was 1970 & '71 LS-5's that did not use this system, but used alternative emissions controlled devices.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
The 1974 49-state 350cid (L-48) engine with automatic transmission did NOT have an AIR system (in California it did). Cars with 4-speed transmissions DID. While I was not stopped last summer for an equipment inspection I did carry a copy of that certification in my car. I would hardly expect that whatever databases the Province of Ontario uses would include this nuance nor would inspectors in their 20s and 30s know of this. Note that this is a visual inspection not an emissions test.
As Mike said all 1973s did have AIR. What changed in 1974? I do not know.
