1967 - early 1968 Mechanical 1 question

[John D.]

Hi:

I have been told that when the early 1968 (October 1967) 327/350 HP cars were being assembled that the Rochester 7028219 carbs were not available. GM substituted a big block carb left over from the 1967 models which was a 7028211 ED Rochester carb. Has anyone heard of this happening? Is this a possible substitution?

Thanks, John

[Duke W.]

Re: 1967 - early 1968 Mechanical 1 question

I doubt it, and the reason is emissions. All '68 engines had to be certified to meet US and (if sold in CA) CA emissions. Being as how carburetor calibration is critical to emissions performance, any non-certified substitutions could have subjected GM to substantial civil and even criminal penalites for not meeting emissions standards, and a carburetor designed for a BB would have substantially different calibration than one designed for a SB.

It is possible that US spec '68 models may have had substitute parts prior to Jan 1,because I don't think the emission standards actually went into effect until Jan. 1. 1968, however, new model year cars were usually certified to meet the standards that applied the following Jan 1. Notwithstanding this, the idle and off-idle calibration of a L-36 carb, would be so different than L-79 that it would probably not meet basic driveability requirements.

Duke

[Joe L.]

Re: 1967 - early 1968 Mechanical 1 question

John-----

The 7028211 carb was not a 1967 model year carb. It was used for the 1968 model year for big block applications in other Chevrolet models but not Corvettes. Since it was used with standard transmission applications, it would have been designed for use with AIR (1968 Chevrolets models with standard transmission and ALL 1968 Corvette applications used AIR; all other 1968 Chevrolet models with auto trans used the CCS exhaust emissions control system).

Nevertheless, I really doubt that this carb was ever used in PRODUCTION for 1968 Corvette with L-79. In any event, it would take pretty convincing documentation before it would ever be accepted as originally used for the 1968 L-79 application.

[John H.]

Re: 1967 - early 1968 Mechanical 1 question

No 1967 (Corvette) ever used a Rochester Q-Jet - all '67 4-barrels were Holleys.