58 Carter WCFB 2x4 Idle Adj Srew Bypass Base Plate

[Eric S.]

Hi NCRS folks,

The service bulletin shows 2x4 with secondary idle adjustment by-pass screw on driver side base plates of Carbs, in addition to the mixture screw in front and the idle speed adjustment screw.

Which Corvettes, Years have this screw on the base plate? Mines does not have.

Thanks,
Eric

[Stuart F.]

Re: 58 Carter WCFB 2x4 Idle Adj Srew Bypass Base Plate

I only saw these on very early twin carb set ups like from 1956. I loved them and don't understand why they were eliminated. They were also on the Cadillac El Dorados, but they ran both primaries together, I.e. Two stage progressive linkage instead of three stage as on your set. Therein may lie the reason.

Stu Fox

[John H.]

Re: 58 Carter WCFB 2x4 Idle Adj Srew Bypass Base Plate

Hi NCRS folks,

The service bulletin shows 2x4 with secondary idle adjustment by-pass screw on driver side base plates of Carbs, in addition to the mixture screw in front and the idle speed adjustment screw.

Which Corvettes, Years have this screw on the base plate? Mines does not have.

Thanks,
Eric

Eric -

The idle air bypass screw arrangement disappeared after September, 1956.