View Full Version : Chrysler 707HA 70HP Surface Gap Plugs

05-28-2009, 02:11 PM
Been asking around about replacing the Surface Gap spark plugs in the motor with a regular type plug. The plugs in it now are NGK BUH Surface gap plugs. NGK said I could but to use B9HS plugs. Has anyone else done this?

05-29-2009, 12:02 PM
"Bill you can go with a Champion L82C or 5931 gapped at .040

The surface gaps tend to run better with alot of open throttle, the gapped plugs are better for cruising or other slower speed operations.

Unfortunately, nothing right down the middle.

The Chrysler iginition system should also work a little better with a Champion plug - NGK's work great in Merc/Yami ignitions which put out significantly more voltage than Chrylser or OMC systems."