Looking at replacing the plugs on a 64 - 390 -

Autolite makes the platinum and the resistor plug - anyone know the difference between these two plugs? Thanks

"Platinum" sparkplugs have a center electrode that has platinum alloy tip which resists erotion and therefore claims to last longer. A "resistor" sparkplug has an electrical resistor built in to supress RFI (radio frequency interference) and may or may not be platinum tipped. A new set of Motorcraft, Autolite or NGK resistor sparkplugs will keep your 390 happy.