the guy who i bought the 308 gears from burned me. however I bid on a set of 355 gears on a whim and won them for 25 bucks. not bad for richmond gears. they were used so i could see how some people would be sceptical of buying a used set of gears, but since they only had 500 miles on them i figured i might as well.
worked out very well for me. I bought a set of timken bearings and seals and rebuilt the rear with 355 gears for just over $100 ;-)
here's a 13 part series for anybody interested in detail on how to rebuild a GM 12 bolt rear and set up the gears properly in their driveway with minimal tools ;-)
first video is linked, its a playlist so if you open the video in you tube it'll play all 13 videos and you can get whatever info you need.