1966 Corvette: Technical Article: Adjusting the Fast-Idle Speed

By John Hinckley, Corvette Enthusiast Magazine
Used here with permission.
Copyright John Hinckley, Corvette Enthusiast Magazine

Reader’s Question: My ’66 327/350 was fairly correct when I bought it several years ago, but it had a Holley, model 1850, universal replacement carburetor on it instead of the original R-3367.

I’ve recently purchased a correctly dated original Holley R-3367 and installed it along with the choke thermostat coil and rod, but I’m having a problem adjusting the fast idle speed.

It works with the engine cold and the choke blade closed, but it only kicks up the idle to about 1200 rpm at cold start, and that isn’t always enough to keep it running without feathering the throttle for the first few seconds. The old 1850 had a screw to adjust the fast idle, but I don’t find one on the R-3367. How do I increase the fast-idle speed?

This 1-page PDF article is linked below: