User56898

need some help decoding my rear end that's in my 67

the only things i could get off were the casting number on the driver side (1285542B) and some other number on pass (GM15)

please help

tom2

Just look at the rear cover. If it has one cover bolt at the very bottom, it's a ten bolt. If it has two bolts level across on the bottom it's a 12 bolt. I think the first gen 10 bolt rears were 8.2 inch ring gears. Most guys will find a Nova rear from the early 70s with the 8.5 gear.

User56898

thanks for the help

i know it is a 10 bolt just wanted to know if it is a 8.2 or 8.5

angel71rs

8.5 will have 2 triangle shaped lugs at bottom sides of casting, like this (post 7):

http://www.hotrodders.com/forum/rear...ing-82449.html

7.5 will have 2 pips in the same spot, but no way will you confuse a 7.5 for an 8.5.

twozs

ssclone

67 didnt have a 7.5. plus the 7.5 cover is different

8.2 and 8.5 uses same cover.

8.5 will have 2 ears on the bottom of the pumpkin at about 5 and 7 o'clock
8.2 will not have them. they have a half circle kind of deal missing from them.

8.2 parts will fit in an 8.5 housing but not vise versa.

8.2 had 9/16" ring gear bolts with reg thread pattern, 8.5 had 5/8" bolts with reverse pattern.

hope this helps

aaron