Packard Forum Index » Post-War (1946-54)

what is the proper and/or best spark plug for a 51-54 Packard, maybe ac45 or champion j8 or??? did the 1954 359 engine use the same plug?

also, does anyone know what plug an Edmunds head used for these cars? thnaks!!!!!!!

Non-resistor plain AC-45. You can still find NOS ones on e-bay. But if you go to a tractor supply store, they still sell them for agricultural use. Same plug, just non-resistor. They typically have green rings on on them.

Regular parts stores still carry the AC-45R (resistor) and all the AC-45R variants (different reaches and heat ranges). But dont use these as you probably have the carbon resistor built into the distributor cap.

Kev, there isn't a carbon resister in the rotor on a 6 volt system, is there?

PS the Autolite website used to have Packard plug recommendations all the way back into the 20s. You can also go on Bendix.com, click on Autolite, and find recommendations.

I use Autolite 303, 306 or 308 (removeable nipple for nickel thumb screw for 34 and back) in all flathead Packard eights that take 14 mm plugs. They are about equivalent to AC46 and Champ J11. They are resistor so I use non-resistor high tension wires, as most cars I work on have radios.

Of course you are correct. My mistake.

I would stay from using any type of Champion plug.

John F. Shireman

Once you select the correct heat range for a particular engine, which isn't necessarily the one orginally specified due to changes in engines, fuels and conditions under which the car is operated, in many years of maintaining Packards I've never noticed any significant difference between Champs, AC, or Autolite though I know others have different opinions. I dislike Champs because of the Cadmium plated shell which is inappropriate prior to 1955 or 56, give or take a year.