Test Results for new Ultimate 17-6903 Coil and Iridium Spark Plugs



I completed a road test for the Iridium spark plug to check the gas mileage. Here are the results along with a comparative to other plugs and coils:
Summary of highway gas mileage using various coils and plugs. The 17-6903 coil is the new "Ultimate Coil" with the towers on the side.

Carbs: Stock BS34's
Exhaust: EMGO 27" reverse cones
Air Filters: Paper element replacements for stock filters
Fuel: 93 Octane
Ignition system: PAMCO 60 degree (except test 1 is 90 degree)
Plug wires: 5K caps

Note: Same 60 mile test route for all results.
Same pump used to refill after each run.
The results for the Iridium plug are impressive. More than I would have thought for just a change of plugs. Of course, this means that more of the fuel is being ignited in the cylinder, so there will also be a corresponding increase in power as well. Because more of the fuel is actually ignited, you can feed more fuel with a larger main jet to further improve performance without sacrificing fuel economy. I installed 135 jets for the last two runs, as shown