I Need help I came across 1971 cutlass 12 bolt complete rear-end and want to know if I can swap in my 1967 cutlass without any major mods ?

 

Well, first of all, there is no such thing as a 1971 Cutlass "12 bolt" axle. All 1971-72 Cutlii received "corporate" 10-bolt 8.5" axles from the factory. You will need to figure out what axle is really in that 71 Cutlass to determine how it fits.

Note that if the "12 bolt" is actually a Type O axle, as used in the 1967-70 cars, then yes it will bolt in. If it is a Chevy 12-bolt it should bolt in, but driveshaft length may vary by an inch or so.

 

What is your goal? What gears are you looking for and where are you located? maybe someone on here has a rearend that would work for you with no questions.

Just a thought

Larry

 

Well I was offer the complete rear end it came out of 71 cutlass I haven't seen it to checkout But let I'll let you know what is. I have 10 bolt on my 1966 cutlass I just wanted to beef up to 12 bolt I live in Puerto Rico old parts are hard get

 

Get us the code from the rearend and some pictures as well. The P series 10 bolt in 66 is a pretty tough rearend. 71 only had a 10 bolt so we need to figure out what the rearend actually is. Get us info and we will help you.

on the right axle tube between the center section and the right spring mount there should be a series of numbers/letters stamped these could be upside down. On the center cast section on the webbing there will be casting numbers in various areas. Get a picture of the cover and take it off and get a picture of the numbers on the edge of the ring gear and count the teeth on it and the pinion gear

 

Be aware that just because an axle has 12 bolts on the rear cover doesn't make it a "12 bolt" axle. The Chevy 12 bolt uses 12 bolts to hold the 8.875" ring gear to the carrier. The Type O uses 10 bolts to hold the 8.5" ring gear to the carrier. Many people assume the Type O is a "12 bolt" since it has 12 bolts on the cover and over-pay for one.

 

any REAR END SWAP WITH A 10 BOLT 8.5 WILL NEED DRIVE SHAFT MIODS DEPENDING ON WHICH WAY YOU GO.
IE IF YOU HAVE a 10 bolt 8.5 and switch to any other rear you will need a longer drive shaft...
IE2 - if you swap IN a 10 boklt 8.5 from any other rear you will need a driveshaft shortening.

NOW that is if EVERYTHING on the existing vehicles are correctly fitted to there original parts. WHICH we all know is usually NEVER the case. Jim

 

DID they still have the 12 bolt Chevys in the Canadian cars as a base rear in 71 72? Also in 1971 1972 The GTO rears were 12 bolt Chevy and the grand prix high powered cars also used the Chevy 12 bolt as the stronger option. Soooo DO your home work. Jim

 

Note No Olds & no Buick made in Canada after 1969.


Base Chevy & base Pontiac A body cars got 10 bolt 8.2.


High performance cars built in Oshawa like 455 HO cars still got Chevy 12 bolt.

 

There you go.