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

[Fred A]

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

 

[RemCharger]

NGK XR5

 

[Welder guy]

NGK XR5 V-POWER

 

[halifaxhops]

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

 

[Fred A]

No mods everything original 400 with lean burn

 

[commando1]

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.