Sparkpug help
 

Im wondering what sparkplug to use in my plymouth ,it is a 1965 belvedere with the 318 poly engine and has a four barrel carb.i think this car only had a two barrel carb from the factory ,what would be a good plug to use.
Thanks for any advice

the champion J14Y was the original plug. I've heard some good things about the NGK plugs. (I always used Autolite plugs in the old days) NO AC's in a mopar please. Got extra dough burning a hole in your pocket, try some Bosch Platinum's. [Just cross reference for the correct number plug]

Thank you mopar guy,im wondering if the plug stays the same or it changes because it was changed from a 2 bbl to 4 bbl carb

Nah! Just stick with the Champions. The factory used them then and they still use them today.

Factory fill on a $100,000.00 DODGE VIPER, Champion plugs. I run them in my Hemi Dart too.

same here
champion all the way

I guess you would use the same plug for the 4bbl in your case. The reason is because the compression ratio has not changed. If you had the hp motor you then could try experimenting with a colder plug (like the J12Y). The colder plugs were used in engines that made more heat I guess to try to prevent preignition in the combustion chamber. I remember it like this. Hot motor-cold plug. Cold motor- hot plug. Mostly this is all old school stuff. I doubt it matters unless you have a race car especially with the new ignition systems available today.

Thank all of you for your help.I will use the plug recommended on this site
Paul