I was reading everywhere how the Autolite 3923 spark plugs were the best for the Dodge trucks, and picked some up today but they are smaller than the plugs currently running. Hand tightened them and still some play..do they only work with the Magnum engines?

Guessing my 1990 V6 convertible needs the larger thread plug?

 

They have been proven to be best for Magnums. As for LA's it may work, but may not be best due to lower the compression. I'm not sure if they are the same thread. But you may need to remove the washer that is on the plug.

 

K, well I returned 3923's today and got some different autolites for my truck that fit perfect..I'm in the middle of completing the tune up and painting the valve covers now. Will post pics of the cleaner engine bay when I finish tomorrow...