Ironhead68, this is something you probably already know, but I'll add it in case it helps others.
My '67 3/4 GMC came original with the Dana 60 with 4.56 gears.
I ran across a late '70s Dodge 3/4 with big V8 and Dana 60. It was a pick-a-part so I got the 3.54 gears with posi carrier for $50. The GMC uses bigger u-joints and different spline on the yoke. One phone call and $20 and I had the right yoke.
3.54 Dana gears are not that hard to find, new or used.
That ratio works well with my 4600# 3/4, SM465 4 spd and 292.
Not the easiest gears to set up, but worth it for me.
