it calls for 3031 in my Sierra manual, seems to work good. Tryed 40.4, 40.9, 41.4 and they go good no signs of pressure, next up is 41.7 and 42.2 that about all i will try. I was happy with the results of 40.9, but just wanted to try more, max is 43.9.
Checked the length for the lands and...