Best Grade of Oil for Racing

[3dinter]

I am going to pose this question and i think based on the area of the country you are from we are going to get different answers based on weather conditions.
What grade of motor oil do you use in your race car engine and why ?

[sj valley dave]

We use an oil tank heater so it's not a question so much of weather temperature, but more a question of bearing clearances and block material. we were running Gibbs XP3 which is similar to a 10-30, but have recently switched to XP9 a 10-40...

[stockcar5]

same here on the xp9. was mixing xp3 and xp6 to get a 10-40 until they came out with xp9. there is a very good chart on gibbs site for selecting oil viscosity.