I hear some people claim it's worth ET and others that don't think so, however, I have to change plugs anyways and it's free, so it can't hurt anything!

This may be a stupid ? but I point the plug where the spark will be pointing towards the intake, correct?

If anyone, can e-mail me or post a good way to go about doing this I'd appreciate it. My e-mail is ss496chevy@hotmail.com

Thanks,

Matt

Indexing plugs, just takes time. You can get a set of shims to allow you do so. Make a mark on the plug that allows you to reference the opposite side away from the ground strap (180 degrees away from the ground strap)You do want the index mark at 12 o'clock, lets the intake charge "see the spark", spark / intake valve not shadowed from the ground strap. Take a plug with your mark on it, install plug. Take note of where your mark is with plug tight, shim plug threads to adjust final install. Worth ET /Power? Some say yes/no. I say it aint gonna hurt and it's a very "hot rod" thing to do. Tell your buds you spent last week end indexing your plugs, they will be impressed. Better than a NOS sticker!!!! :cool: Without the shims you would have to score a gob of plugs and or try different plugs on different cylinders to get close to your index mark at 12 o'clock installed position. That's where the "it takes time" thing comes in.

I am running Autolite 25 spark plugs. I was considering going to Autolite Racing AR25 plugs. They have a cut back ground strap, I guess that would do away with any potential benefit from plug indexing. I do not know if there is any other difference in the 25's verses the AR25's other than the "shorter" ground strap and the price. That's a 1.39 verses 5.00 a plug around here, and they have to order them and it takes a week to get them. graemlins/angry.gif

Thanks for the info, I thought I knew how to do it just wanted to make sure.

I'm running AC R44XLS plugs. Are the Autolite suppose to be the better plug? I've got 206 oval port closed chambered heads. And they are still the big 13/16 plug.

Any ideas on what plug would be better for me?

Thanks, Matt

Matt, I dont know squat about plugs. I do know that plenty of folks are happy with AC plugs, many folks here love them. Some spark plug guru will be along shortly to help out..........

Indexing may also be important if you are really close btwn piston and spark plug, i.e. you want the heal of the ground strap up not down for max. clearance. I also run Autolite AR plugs due to the cut back grounding strap.