As a ball driller myself, i have to disagree with everyone here who has been recommending 5" pin to paps on his sym cobra.... His speed is actually more dominant than his revrate, especially when u factor in his high tilt and medium high axis rotation, these two things are going to add length thus can be thought of as increased speed. I would strongly say to go with a low ratio, although on a sym the thumbhole will be the psa, but anice size/deep hole 2" down your val, from your midline will help decrease this drilling angle. And a 60-50 degree val angle with a pin distance no more than 3 3/8. Which would be great since the cobra has a very low differential to start with. But i also like the idea of a 2.75" pin
Trust me.... 5" pins are specifically meant for those with a lot of hand andf roll looking to preserve the little bit of tilt that they initially have.
Sean