Back in the day there was a lot of talk about indexing spark plugs for maximum power, and this came from the fact that cylinder heads weren’t the epic flowing monsters that cylinder heads have become today. Hell, a factory LS or LT cylinder head is better than a lot of race-only parts that existed 20 years ago. So back then there was a school of thought that said that indexing spark plugs was good. There were also some applications where indexing the plugs gave better clearance in the chambers on heavily domed pistons.
But ultimately, is there a need? Especially on an LS engine. And if there is a benefit, which direction should you index the plugs?
How the hell do you index spark plugs anyway?
Watch Richard’s latest video for all the info.
WHAT THE HECK DOES INDEXING A SPARK PLUG MEAN? CAN YOU INCREASE POWER BY INDEXING SPARK PLUGS? SHOULD YOU EVEN WORRY ABOUT IT? HOW HARD IS IT TO INDEX SPARK PLUGS? WILL IT ADD MPG? CHECK OUT THIS VIDEO WHERE I STARTED WITH A BTR-CAMMED 5.3L L33 EQUIPPED WITH A FAST INTAKE, THEN INDEXED THE PLUGS SO THEY ALL AIMED AT THE SAME SPOT ON THE COMBUSTION CHAMBER. I THEN AIMED THE OPENING OF THE ELECTRODES OF ALL PLUGS AT THE INTAKE VALVE. I THEN DID THE SAME WITH ALL THE ELECTRODES AIMED AT THE EXHAUST VALVES! WAS THERE ANY POWER GAIN FROM ALL THIS WORK? CHECK IT OUT!