What are the best spark plugs to use on 1978 Chrysler 400 engine?

Fred A · Sunday at 7:50 PM

RemCharger · Sunday at 10:50 PM

NGK XR5

Welder guy · Monday at 12:33 AM

NGK XR5 V-POWER

halifaxhops · Monday at 6:16 AM

Tons of variables here. any Mods? I would read the plugs in there now and go from there hotter or cooler.

Fred A · Monday at 8:38 AM

No mods everything original 400 with lean burn

commando1 · Monday at 10:27 AM

Fred A said:
What are the best spark plugs to use on 1978 Chrysler 400 engine?

Exactly what the manual calls for.
Any of these fancy whoop-di-doo plugs will not give you even 1 hp more on a 45 yo engine.