Spark plug gap and thoughts on side gapping plugs

Hey guys.

I set my plugs at .040 when I did the build and since I have went to the FItech set up I plan on checking and doing some spark plug tunning when I get back to the states. With some of the research I have done on this, I have read that you should gap your plugs smaller when you are making more power. With that said, should I gap them back down to .035? Should I go lower? Also, I read about side gaping spark plugs and am curious if any of you guys have experience with this? One artical I read stated that this could be good for 3-5HP. Don’t know how much water that holds, but just wondering your guys opinions.

Howdy Back 69Stang:

Plug gap and power is very subjective and muddied by several other factors such as, weather, carb/choke tuning, condition of the rest of the ignitions, variables from situation to situation, etc... But, you can do your own assessment by starting with a well tuned engine with known plugs and gap width. Do a timed test of, say 20 to 40 mph in one gear. Do it three times for an average. Write it down. Try to replicate conditions on each test for reliable comparison. Then make the change you wish to assess, repeat and compare results.

I am not aware of any performance increase by narrowing the gap. Please enlighten me.

Adios, David

If you don't mind spending the extra $'s go with NGK 7510. They are Iridium & gap them at .045" The center electrode is thin & the side electrode is pointed & does not completely cover the center electrode. They supply a better flame kernel.
I have run them for years with great results.
Do not use them in a supercharged engine cause the piston does does not like the hard center electrode if you go into detonation.