12 bolt rear end

[bbbc10]

are the 67-72 12 bolt rear ends an 73-87 12 bolt rear ends the same diff cover bolt pattern? reason I ask is I have a 12 bolt rear end that was under my 81-87 swb frame an a guy is selling a watts link that is for 67-72 12 bolt rear end an I need to knw if it will bolt up to my 12 bolt rear end

[69heavychevy]

covers are the same, btw 80 was the last year for 12 bolts. mounting points/dimensions are different, also have to figure trailing arm/leaf spring differences

[bbbc10]

Im not worried bout all that....i jus need to knw if the bolt pattern for the diff cover is the same

[friscobob]

My 81 seems to have a 12 bolt.

[Bloodhound]

Originally Posted by friscobob

My 81 seems to have a 12 bolt.

Same here. I thought 81 was the last year.

[friscobob]

Originally Posted by Bloodhound

Same here. I thought 81 was the last year.

Did the 12 bolt end in 81 or? What was it replaced with? Is the replacement a bolt in for earlier chassis? Which is better, 12 bolt or later?
Bob

[Matt Man]

12 bolts were available until 81 (my truck has one with a detroit locker) Starting in 1982, the trucks came with the corporate 10 bolt rear end pretty similar in strength but the 12 bolt has bigger axle shafts, but a smaller pinion gear. However, the pinion gear usually doesn't break on 12 bolts, but the 10 bolt rear ends break axle shafts easier.

I think parts are cheaper for the 10 bolt, you can build both to be pretty strong. But in a stock comparison, the 12 bolt is stronger.

[69heavychevy]

I stand corrected...