AC Delco Spark Plugs
Needing to know factory correct spark plug for 1963 Cadillac. I assume it is either the AC-44 or AC-45 spark plug with the green rings but can someone let me know if this is correct and if so which one? Thanks, Doug
Needing to know factory correct spark plug for 1963 Cadillac. I assume it is either the AC-44 or AC-45 spark plug with the green rings but can someone let me know if this is correct and if so which one? Thanks, Doug
David Thomas
The AC 44 was the factory recommended plug for all around use. The 45 was an optional one step hotter and the 43 is optional one step cooler. You would use the hotter plug for low speed city driving IF there was a fouling issue with the standard plug, on the other end; you use the cooler plug for continuous high speed IF the standard plug ran too hot.
Apr 28, 2015
William Cameron
your post on spark plugs could be a good addition for "Help Topics"
Apr 28, 2015
Jason Edge
If looking to stay original the R44 (resistor plug with part # 556 9993) was used with cars equipped with am/fm.
Apr 28, 2015
Jason Edge
Doug, If you missed it be sure to check out John Washburn's Article on AC Spark Plugs in the Sept 2013 Self Starter. I was trying to find another article he did on another subject and found that piece. Jason.
Apr 28, 2015