Obviously cutting the ground strap back on your spark plugs is an age old argument. Some say it works, some say it doesn't. Regardless, I have done it and will probably continue to do so which leads me to wanting to know more about it. That being said, I have a couple questions regarding side gapped / trimmed spark plugs. FWIW, I will be using Autolite 85's this time around because that's what I have sitting on the shelf. So,

1.) Is it better to end the ground strap above the electrode or carry the cut back to the edge of the electrode?

2.) Is it better to leave a flat edge across the front of the ground strap or is a pointed edge ok?

3.)What is your reasoning for your opinion on this? Back it up.

Just because I started this, I'll begin by pointing out that several spark plug manufacturers have begun to produce plugs in this style. They must do it for a reason. No I don't think that the automotive manufacturers are stupid and don't know about this, they do have to consider maintenance intervals and as such, most likely don't want to risk reduced plug life. Furthermore, I have yet to see any documented gains from this but I believe as minimal of a gain as it may be, the logic behind it seems to lend hope to making more power.

And begin.

I buy the C61CX or C59CX and just leave them. strap ground back design.

http://www.carcraft.com/howto/116_0703_spark_plug_guide/viewall.html

I`d buy em done that way not bend em myself for fear you`d weaken the ground strap and find it in a cyl.........

I have a good freind who grinds or clips the ends off of those plugs he wants to side gap, he has bent and broke them off before in the past before changing to grinding or clipng them off

A little on the old school side, but the idea was that it was easier for the spark to jump the gap from a sharp edge and it uncovered more of the spark to the AF mixture ( not as shielded by the ground strap ). Many racing plugs come that way these days. Pic is of an NKG 9 race plug for a small block. They helped if you had a marginal ignition system. Todays ignition systems can operate in the 50 - 55K voltage range and will light your cigar from 10 miles away. They also helped to eliminate carbon bridging ( crap getting stuck between the electrode and ground strap ).

I know they can be purchased as such now. I'm a low buck kinda guy for the time being though. At over 2x more to purchase them done I just assume take the time to do it myself. I typically cut them back to about 1/3 cover over the electrode and it leaves a nice point on the ground strap. Alternatively I've read that some people buzz them off straight using a Dremel and a zip disc. I was just curious as to what the ideal method was. The mystery continues.

I've been going this since the early 80's. Some combos like it and some don't seem to care. I've done both the clip as well as cutting them back with a jewelers cutoff wheel(similar to the dremel deal),never had the tip fall off after this mod. guess I'm not doing something right?