What Is the Plug Gap for a 1991 Chevy 350?by Justin Chacos
The Chevrolet 350 is an endearing small-block V-8 which has a long history in a vast number of Chevy models. It was introduced in 1967, stuffed under the hood of the Chevrolet Camaro, and by 1970, the 350-cubic-inch engine was available in all of Chevy’s now-classic muscle cars: the Nova, Camaro Z28 and Corvette. Fast-forwarding down the evolutionary line to 1991, the engine was available in such GM models as the K1500, Corvette, Caprice,and Brougham.
The appropriate spark plug gap for the Chevrolet 5.7-liter 350 V-8 is 0.035 inch. There are several tools you can use to both measure and adjust the gap. A simple feeler gauge can be used to measure the gap. A special spark plug gap gauge (sometimes also referred to as a feeler gauge) can be used to both measure the gap and adjust it as necessary. Additionally, many auto parts store stock keychain spark plug keys near the registers. Although these are convenient to have, their calibration is questionable after the wear and tear of daily keychain life.
There are two things to note when gapping the 350 spark plug. One, some spark plugs cannot be gapped. It may be physically possible to gap them, but they are not designed for adjustment. Secondly, always verify the new gap after adjusting it.
Justin Chacos is a professional mechanic with experience on all vehicle types, from cars to boats to airplanes. He has been writing since 2006 and has been published in multiple maintenance manuals and journals. He holds a Master of Science from the University of Arkansas.