It moves the veins and surface where a stuffer bolts up closer to the impeller. Alot of shops used to do this.9 times out of 10 the machinist that did the work didn't quite have a handle on what he was doing and it didn't get done correctly. It can be checked to see if it was done right, also the wear on the bushings is a way to tell if something isn't right.
Meaning machined incorrectly. That machined face must be perfectly square to the bore where the bushings are.i'm curious as to what you mean by that? As in he took to much off or milled it off center or?? Seems to be with a G bowl it pretty much straight forward....a C well not so much.
be safe , frank.