When running higher than stock compression (10.6:1) what plugs are recommended?

And what are equivalent to the HD plugs?

 

HD's are good as any...stock, or modified...

 

We use NGK DCPR8E

 

NGK DCPR8E's gapped at .035".
Scott

 

Thanks, all.

 

Another vote for the NGKs; I like the 9Es, just a range cooler.

 

DCPR7EIX at .035

 

When I was into stock car racing I remember that the rule of thumb was to run the coldest plug you could without fouling.

 

The HD 10R12 plugs are also an option. I used them on a previous build and just 1 or 2 ranges colder than the stock 6R12. I like that they have a solid connector tip like stock and won't vibrate loose.

http://www.harley-performance.com/ha...park-plug.html

 

Seems like I remember reading somewhere about the newer ECM systems using the plugs and wires to get readings and they don't recommend changing from stock because it will affect those readings negatively. I'm thinking of relocating my coil and haven't done it yet because of this. Anybody know if this is true or ???