nitro or nothin

I bought the nova head for my hyper .21 (link, http://www.novarcproducts.com/racepro.html) but I noticed that the mcoy #8 plug I was using in the the factory head, wich sat flush with the top of the comustion chamber, is short in the nova head (about 1 1/2 threads) I know this is going to decrease compresion, wich I don't want. I need to know if there is a longer plug I can use? I would like the bottom of the plug flush with the top of the combustion chamber. Can anyone help me

DAVCOM

being a novice in this only a yr in nitro i would personally contact nova and ask them .From what i had learned here is ask manufacturer .. just to be safe.. sorry i can t be more help..

nitro dipstick

You did not mention what fuel you are using, but I don't think the plug will decrease your compression enough to be noticeable. You can also try a MC 9 (cold) or an OS A5 (med / Cold) or the OS R5 (cold) plug.