spark plug choice for 440

[brian/heather]

i was wondering if you guys could tell me what would be the best spark plug choice and heat range for my 440 with an MSD ignition. thanks for the help

[Kern Dog]

Sure...maybe first you could tell us more. To give you an accurate suggestion, what camshaft, compression, cylinder heads, carburetor and the overall miles on the engine. The reason that there are hundreds of spark plugs available is because there are thousands of variables to sort through.

[404NOTFOUND]

The MSD box is so potent, the regular Champions will be all you could ever want. Try a .050 gap at least.

[Kern Dog]

The MSD has proven to only have multiple sparks at lower RPMs. More sparks do not make up for that huge of a gap. Make the gaps THAT big and you risk misfires. You may have to wait until Monday and call MSD to see what they suggest.

[404NOTFOUND]

The MSD has proven to only have multiple sparks at lower RPMs. More sparks do not make up for that huge of a gap. Make the gaps THAT big and you risk misfires. You may have to wait until Monday and call MSD to see what they suggest.

It's not just mutiple sparks. It is very strong voltage too. If I remove the coil to cap wire and crank the engine, it results in a powerful lightning storm under the hood, enough to actually frighten people who see it. I dare them to put their hand in there. No takers yet.

[Fred]

The MSD has proven to only have multiple sparks at lower RPMs. More sparks do not make up for that huge of a gap. Make the gaps THAT big and you risk misfires. You may have to wait until Monday and call MSD to see what they suggest.

I'm inclined to agree with you Red.


I'd recommend NGK-BP5S plugs (not sure if the numbers are the same in the Us though).

[Just 6T9 CHGR]

NGK XR5 are a great 440 plug that I have been running for a few years 

[Chryco Psycho]

Gapping more than .040 is hard on the wires as well , I would just use the Champion RJ12YC plugs