Champion 802 V63C. Recomended by my machinist so I use them.

Rapidfire #1, Smooth idle no problems:D

We just got done replacing my A/C R44TS with MR43T and all of them were very black (Rich?) But then on the second motor the #5 and #7 had burned the electrode completely away!! It even started to burn the ground away!?!?!???

What does that mean? We asked a area Race car guy and he said it usually means that you are burning water and way to hot!?? Then one of you guy's said that you had the same thing happen to you after a long run!! What do you guy's think?

Funhome, I was burning water on two cylinders before a rebuild. My plugs were clean. They were getting steam cleaned. You may be having detonation if the plug ground and tip are burned away. Change your plugs and try a higher octane to control the detonation.

Funhome,

I would check to make sure that the # 5+7 wires are in good shape and totaly seperated from each other. How does your cap look? You might be detonating. Just a guess :)

Many of you seem to like the Rapid Fire #1. Is this plug ok to use with a 1998 502 MPI?

Thanks,

Padraig,,,, Yes you can,,, I am running them in a 97 502 MPI.

Heres a site that gives some good info on plugs. Also there is a page that has pictures of different conditions of plugs.

http://www.centuryperformance.com/spark.htm

Here is what I know. (or think I do :D )

AC
MR43TS - extended tip marine - No longer available
MR43T - non-extended tip marine - available.
R43T - non-marine (no corrosion resistance)
CR43TS - extended tip non-marine commercial
CR43T - non-extended tip non-marine commercial

Champion
RV15YC4 - extended tip - non-marine (no corrosion resistance)

NGK
BR6FS - corrosion resistant

AC Rapid Fire #1 - corrosion resistant

Thanks Guy's!! This place is the BEST!!:D