Clearance is block specific. Some need it and some do not. I only had the one to modify slightly and I chose to make that modification than grind the block.
Cam I used was a Crower Beast cam with if memory serves under 0.600 lift and ~ 255 degrees of duration of 0.050 on a 112 degree LSA. Fairly mild roller. The springs were purchased for the cam from Crower for the cam. No pin oilers on these lifters.