Rocker Arm Shaft Set 216

[chevyky]

My mechanic suggested i replace the rocker arm shafts in my 216 engine because there is some visible wear to the shafts. I got a set from Bowtie Bits.

The issue is that my mechanic pointed out that the bottom of the shaft is slightly ground along the length of the shaft( http://www.flickr.com/photos/union44...7623358552886/). Our old set of shafts does not have the underneath grinded. Does anyone happen to know why? My mechanic thought that perhaps this was an improvement... that GM or someone determined that the oil will flow better with that area grinded down a little.

We're concerned that with the grinded area, the oil wont spread around as its intended to do.

I appreciate your input as always.
http://www.flickr.com/photos/union44...7623358552886/