Bridging The Gap
Some Corvette engine combinations like a bunch of gap and others don'trun well until the gap is tightened up. A gap of approximately 0.025inch is commonly used, but some combinations (particularly those withhigh-powered contemporary ignition systems) can fire a gap ranging from0.045 to 0.060 inch. In all situations, the gap, air/fuel mixture, andheat range must be coordinated to produce the best possible results fromthe engine. In simple terms, it's a case of trial and error coupled withthe correct reading of the spark plugs.
Conclusion
Once you have the correct heat range dialed in, the gap sorted out, thespark plug type selected, the jetting squared away, and all of the othervariables inside your Corvette handled, there is no need to continuemessing with the plugs. The idea is to get your combination set upcorrectly, and to use the spark plugs as a tool in the setup. Onceeverything is right, no magic power will be found in the spark plugs. Remember, they're the window inside your Corvette engine. Don't forgetthem.
 After the appropriate washer...  After the appropriate washer is installed on the spark plug (you mighthave to try several different washers on each plug), simply tighten theplug in the cylinder head. Given the varying washer thickness and thesoft nature of the copper gasket, you can adjust the index mark on yourspark plug so the electrode is correctly situated in the cylinder.Here's a tip: In most Corvette cases, the engine responds to a gap thatfaces the center of the cylinder or angled slightly toward the exhaustvalve. On the other hand, some combinations prefer different electrodepositions. |
 Today's ignition systems are...  Today's ignition systems are sophisticated, but don't fall into thistrap: They have absolutely no effect on jetting and cannot change theair/fuel ratio. That's the job of jets. But when a modern, high-poweredignition system is installed on an early point-trigger Corvette, thejetting almost always appears lean. Why? Simple: The new wave ignitionsystems offer much superior burning property. Because of this, changesmay be required in the air/fuel ratio. |