when I order my cam I will ask about this Mod...

I ran across it in my daily learning (research)

the base part of the lobes are cut back and give less friction
this is used in a very reliable engine... so the design is proven with many, many, miles on it... the engine that uses it do not fail...

 

The base will not be touching anything, so there will not be much reduction of friction.

I think it's done to improve balance or to save weight.

 

Leo is right. There is virtually zero friction when the cam is on it's base circle due to the physical clearance between the cam and the valve bucket.

 

both above correct, and it is for hydraulic followers, and it helps to rotate the follwer when on base circle!

pretty simple stuff, seen it before!