Exhaust mainfolds, CWR and CWS engines

[Jean C.]

I am attempting to help a '74 owner with resolving a couple of issues but I do not have a '74 TIM&JG.

Are the exhaust manifolds on a '74 CWR (454/270) the same casting # as the CWS (California 454/270) engine? (I say they are because the NCRS Corvette Specifiataions Guide makes does not differentiate between the two).

Does the '74 CWR engine have the AIR emissions system? (I say it does and thus should have drilled exhaust manifolds).

The car owner is presumably of the opinion that only the CWS (California) cars have the AIR emissions system. I am of the opinion that all 454's in '74 had the AIR system (as is the case of 454's in the '72 TIM&JG) and that the difference between CWR and CWS was a different cam used in the CWS engine, e.g. longer valve overlap.

Sure would help if I had a '74 TIM&JG!

Thanks and best regards,

[Mike M.]

Re: Exhaust mainfolds, CWR and CWS engines

my 74 454 coupe, bought from one of my firends and with just 20K miles on her, has the exhaust manifolds drilled for the AIR tubes. mike

[George W.]

Re: Exhaust mainfolds, CWR and CWS engines

Charlie, the 1973-74 TIM&JG, second edition with updates, states that on LS4
"All are tapped for A.I.R. injectors".

George

[Joe L.]

Re: Exhaust mainfolds, CWR and CWS engines

I am attempting to help a '74 owner with resolving a couple of issues but I do not have a '74 TIM&JG.

Are the exhaust manifolds on a '74 CWR (454/270) the same casting # as the CWS (California 454/270) engine? (I say they are because the NCRS Corvette Specifiataions Guide makes does not differentiate between the two).

Does the '74 CWR engine have the AIR emissions system? (I say it does and thus should have drilled exhaust manifolds).

The car owner is presumably of the opinion that only the CWS (California) cars have the AIR emissions system. I am of the opinion that all 454's in '74 had the AIR system (as is the case of 454's in the '72 TIM&JG) and that the difference between CWR and CWS was a different cam used in the CWS engine, e.g. longer valve overlap.

Sure would help if I had a '74 TIM&JG!

Thanks and best regards,

Charlie------


With ONE exception, ALL 1974 Corvette engines were equipped with AIR. The exception was L-48 with automatic transmission and federal emissions (engine code "CLA"). I don't have a 1974 JG, either, but if it says anything other than this, it's incorrect.