Harper220

I have the 496 mag HO and have never changed the plugs. I would assume the factory plugs are still in. What are the best performing plugs for this engine and the correct gap? Are there any that out perform the factory recommended plugs?

Harper220

Griff

The factory plugs are supposed to be good for 300+ hours. I would guess at $15 each that they are probably the best.

Dennis Moore

The 496 has such an excellent ignition system that unless you have put a lot of hours on your engine I wouldn't think that changing spark plugs would do you any good. Pull the plugs and inspect them. Look to see if the electrode has the edge rounded off. It should still have a sharp edge. The spark likes to jump from a sharp edge on the electrode to a sharp edge on the ground strap. Hard electrodes (like platinum) stay sharp a long time.
The difference between performance plugs and long lasting plugs is the hardness of the electrode. A hard electrode (like platinum) lasts a long time but is a poor electrical conductor. A soft electrode (gold, silver or copper) conducts electricity very well (for performance) but wears out quickly.
Take your pick, performance or durability!
Sincerely
Dennis Moore