Originally Posted by
miket
The plug is a OD 99. and I'm running OD fuel 20%. When you said mc-8 are you talking about a McCory plug. I have been adjusting the lsn trying to get the motor to have a steady idle may be to lean on the bottom. Glad to know the pipe is correct with the header.
Yes I am talking about the Mc Coy plugs. I believe the OD99 is colder than the MC-8. Since you are running 20% try the MC-8 as is, and see if there is any gain. If your idle is not steady, the tune is not quite right, which is good news for you as performance will get better when you get it nailed down. My car will literially sit and idle for 2 minutes easily. If the tune is right it should start to load up at idle after 10-15 seconds or so. This will happen quicker as you run colder and colder plugs.