Use a number 9 plug preferrably MC 9 or dynamite 9 (They are the same) Or an alternative is a number 8 novarossi or RB. That engine will kill anything colder than that due to combustion turbulence. The 9 will give you more off the corner torque. Be sure not to overlean the low end. It should struggle to shift the first 2 laps of warm up (the low end needs to be that rich) The top should be around 4 1/2 and the bottom 3 1/2 from closed. After the five minute warm up the engine should be 220 to 240. It will come on at the 7 minute mark and should come off the track 245 to 265. Low speed in many cases will have more of an effect on engine temp than the top.