#3984831 ring gear. 12:41= 3.42 gears for a corporate rear end I am guessing? not sure of the exact years these were used…..almost no wear. Gears are really clean. Asking $300 plus shipping. PM or text 661-203-6953. Thanks, Dave

 

Anyone knowing the exact application please add in. These were in my dad’s garage when I cleared it out. I’m a 69 guy and that’s mostly the year range I know. Hopefully someone can use these.

 

Could be O-Type or corporate 10 bolt as both had that ratio and both are 8.5" ring gears. The ID of the ring gear and the bolt circle will be different between the two.
I have this info from an old file:

Ring Gear ID:
O-Type = 5.24"
8.5" 10 bolt = 5.00"

Ring Gear Bolt Circle inside edge:
O-Type = 5.856"
8.5" 10 bolt = 5.772"

 

Make a reasonable offer….perfect performance street ratio to replace that lane 2:56/2:78 ratio