Originally Posted by
disaster999
The most important thing about the diff rings is you want to get it as flat as possible. kitchen counter top or a piece of glass works best and apply even pressure across the ring to minimize high and low spots. Usually the right side wheel hub makes a good diff ring holder.
Or just buy TKO's flat and finished differential rings.
http://tkocompetitiondev.com/index.php?cPath=151_145
Best differential rings available IMO.