How to Install Plugs on an LT1 Engine

by Floyd Drake III
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First introduced on the Chevrolet Corvette in 1992, the generation II LT1 engine is a high-performance small-block engine that hearkens back to the 1970 generation I LT1. Displacing 5.7-liters, or 350 cubic-inches, the LT1 is found primarily on Corvette and Camaro Z28s from 1992 until 1997, when it was replaced by the LS1 engine. Changing spark plugs on the LT1 is not an inherently complicated task, but is considered a tedious one, with spark plug access being the most difficult part. By using the correct tools and following the steps, the job can be finished in an afternoon.

Step 1

Set the gap on all the new spark plugs at .050, using a spark plug gapping tool, and apply Anti Seize onto the threads of all the spark plugs. Remove the positive (red) battery cable from the battery terminal.

Step 2

Jack up the front of the Chevrolet. Before jacking up the vehicle, shift it into park, or in gear and place blocks behind both rear wheels to prevent movement. Properly jack the front end of the vehicle, placing the jack under a solid foundation. Be sure to have two jack stands ready, to place on a solid frame area, one on either side of the vehicle. Be sure to leave yourself working room when situating the jack stands. Once the jack stands are in place, carefully lower the vehicle onto the stands. Never work under a vehicle solely supported by a jack.

Step 3

Change the spark plugs on the driver's side, which are best removed from under the vehicle. Working one plug at a time, remove and re-attach each individual spark plug wire with each plug change. Begin with the number one plug at the front, working in order, three, five, seven towards the rear. The driver's side are the easiest plugs to change.

Step 4

Replace spark plugs eight, six and four on the passenger's side, working from the rear to the front. These must be accessed from underneath the vehicle, using different extensions and swivels to find the right combination to complete the task.

Step 5

Change spark plug number two. The forward-most spark plug on the passenger's side is the most difficult, since it is located behind the exhaust manifold. First, remove the alternator and belt in order to access the spark plug. A ratchet swivel and short extension are necessary, and a shortened 5/8-inch spark plug socket also helps. It may be necessary to turn the socket with the box end of a wrench to accomplish this.

Step 6

Re-attach the alternator and belt. Ensure all the spark plug wires are attached and jack up the front end to remove the jack stands. Slowly lower the vehicle back to the ground.

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