Spark Plugs

[Jesco]

Hi,
Any recommendations on Champion spark plugs to a 440 with indy heads?

RJ12YC?

[Challenger340]

INDY Heads use a long reach type Spark Plug, read "long threads", like a small block spark plug.
Standard 440 plugs are short thread. Do not use.

Go in the Champion Performance Catalog. Try a C51 plug, or do hotter or colder range, dependant on your engine build.

Hope this helps.

[Jesco]

Thanks, Found on Indys homepage that RC12YC will work to. Whats the diffrens on RC12YC and RC9YC, something with colder and hotter range?

[Jesco]

Find it my self, higher number is hotter...