still trying to find the right parts for my 66 12 bolt i found on ebay a gm differential #edb-30174 what do you guys think?? is that the one. how do they compare to the eaton? also i see some people putting years on the parts arent all 12 bolt the same as long as its 30 spline? will the edb-30174 work with any ring and pinion i know its a 4 series so i am looking for richmond 4.10's

EDB30174 is the Eaton 4 series posi for 3.90 and up gears.
Here's a 12 bolt part's list ,should you need it http://www.jdrace.com/Rear_ID/12bCHEVY.htm

man you guys are quick. i thought the eaton was #19554 or 19555. How about the ring and pinions one guy on ebay has richmond 4.10 gears 69-70 does the year make a differance?

As long as it's a thin 4.10 it will work. The thick 4.10 will work on a 3 series. I've got a rebuilt 4 series Eaton and good used 4.10 gear that I'll sell if you need them. biggearhead@bellsouth.net

All that within an hour:thumbsup:

not bad