Craft recommended/required for warranty Joe Gibbs Hot Rod
oil 10w30. The explanation for high
zinc, in a roller motor, high spring pressures essentially squeeze the
oil out while the motor is off.
Zinc clings to the parts, preventing a "dry" start. That's what I was told, anyway. A lot of the guys also use Valvoline high
zinc, I believe it is called VR1, not 100% sure.