They work just fine. I used them one weekend leading and trailing.

No problem at all. We got the NGKs for free, so it seemed pointless.

I have also rebuilt other racers engines and they had the Autolites installed. The wire tip end is solid, so it cannot unscrew. The side electrode is cut down so part of the center electrode is exposed. A NASCAR idea. The gap can be changed.

 

I use the NGK 11.5 heat range gapped at .010" One MSD6AL for leading and trailing. Inductive wires.

Never a fouled plug. Never a misfire.

 

If you doubt that any plug might damage a housing because it is too long, just stick a blob of modeling clay on a plug and screw it in hand tight with no gasket washer. You can chill the plug before doing this so the clay stays on the plug. It will come out with the shape of the plug well molded into the tip. If the ground electrode is not showing through the clay you are good to go with a gasket washer installed.

 

Check that the Autolite is the crossover heat range for an NGK dash 10 plug.

Looks a bit colder to me. The stock plugs that look like aircraft plugs appear to use the aircraft system of shielding the center core with the 4 wide ground electrodes to make up a wider heat range.

 

When you think about heat ranges, think duty cycle. In racing we think that is the worst high stress application. It is not. In racing every few seconds we are at idle throttle setting with the engine screaming and idle mixture cooling the plugs and engine internals. This during hard braking.

In the aircraft it is minutes of WOT even in the pattern doing touch and goes. For cross country its WOT to 6,000 feet then lean to cruise and an hour of WOT or more.

 

Aircraft use has the very highest duty cycle of any application. Using a street plug is nearly suicidal.

 

Lynn E. Hanover

 

 

 

In a message dated 10/9/2012 11:28:31 A.M. Eastern Daylight Time, msteitle@gmail.com writes:

As I recall they have a typical side ground electrode.  I doubt those
would work in the trailing hole.