Side gapping and plug indexing

I was curious if anyone here has much experience with side-gapping or indexing spark plugs. These techniques have been around for years, and seem to have legitimate claims of making a few hp by improving combustion efficiency. For those who are unfamiliar, here are a few articles explaining each:

Side Gapping

Plug Indexing

The consensus with the Mustang guys over on Corral.net seems to be that indexing "can't hurt and might help." Side-gapping also has its proponents, and the only side effect seems to be shortened plug life. Some say that trimming the ground strap back to the center of the electrode is nearly as effective as trimming to the edge, with better plug life.

I figure these are a few ways to gain a few extra hp for free. Anyone have any first hand experience?

I've done both. With indexing, those spacer washers allow the plugs to get loose after several hours. I think it ran better, might have been my imagination for all the effort. My brother in law was into go cart racing and on a small engine like those they could gain 1 horsepower from indexing.

Tim D wrote: With indexing, those spacer washers allow the plugs to get loose after several hours.

Im thinking it would probably be better to just keep trying different plugs to avoid using washers. I a$$ume you side-gapped the plugs on your boat at the same time you indexed them?

    I would think in a race application where every detail counts,it's worth it.I can't imagine you would notice a huge(or even noticeable)difference in your application Tim.I would take 79's advise and buy a real good set of plugs and wind em in.But then again,the winter is alot longer up here than it is where he's from,at least it would help pa$$ the time

   Mike

05 210 wrote: But then again,the winter is alot longer up here than it is where he's from,at least it would help pa$$ the time

Thats what Im thinking. The only downside is time- and we have plenty of that before the ice breaks. Im not too worried about the shortened plug life- theyre cheap and I change em every season anyways.