Will it fit?
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Joined: Jan 2013
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From: Sulphur Springs, Tx
Will it fit?
I have a 1970 Cutlass Supreme with the 12 bolt "O" rear end. I just bought a complete complete 1974 442 car that Im probably going to part out. My question is will the 442 rear from the 1974 bolt right in where my 12 bolt resides now?
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From: Delta BC Canada
Old(s) Fart
Joined: Mar 2007
Posts: 50,770
From: Northern VA
The 1973-77 cars have a wider track width (and thus a wider axle) than the 68-72 cars.
Seasoned beater pilot.
Joined: Jan 2007
Posts: 5,468
From: Chicago
The width difference is minimal. 55" between the backing plates on the o type, vs 55.5" between the backing plates on the 74.
Your problem is the shock mounts, and upper ears as 507OLDS said.
o type the shocks mount rear of the axle, and 74 mount in the front.
The upper ears on the o type are on a 45? degree angle, and the 74 is more like a 30 degree angle. It'll bind like crazy.
Your problem is the shock mounts, and upper ears as 507OLDS said.
o type the shocks mount rear of the axle, and 74 mount in the front.
The upper ears on the o type are on a 45? degree angle, and the 74 is more like a 30 degree angle. It'll bind like crazy.
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Joined: Feb 2013
Posts: 15,394
From: Phoenix, AZ
Back in the 80s I tried installing a '75 rear into my '70 Cutlass and almost killed myself. I was using a bottle jack to lift the rear into the mounts and it wouldn't go. Kept lifting with the jack to force it in, ended up lifting the entire car off the jack stands; car slipped sideways and fell off the jack stands while I was still under it. Luckily, the lower rocker lip on the side I was on caught the cradle of the jack stand and kept the car from crushing me. Had to manipulate the bottle jack to lift the car off myself while I was pinned under the car. I remember that day very vividly.
The moral of my long winded story is: Don't try to put a 73-77 Cutlass rear under a 68-72 Cutlass - it will not fit.
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Joined: May 2011
Posts: 3,688
From: Delta BC Canada
Fyi
Any 1971-72 GM A body rear end will bolt in. All will require a change in driveshaft. The 71-72 Olds & Buick have bolt in axles. The Chevy same year uses C clips. The Pontiac is an 8.2".
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Joined: Aug 2013
Posts: 3,900
From: Central Illinois
The mismatch is such that you cannot install the rear into the control arm mounts.
Back in the 80s I tried installing a '75 rear into my '70 Cutlass and almost killed myself. I was using a bottle jack to lift the rear into the mounts and it wouldn't go. Kept lifting with the jack to force it in, ended up lifting the entire car off the jack stands; car slipped sideways and fell off the jack stands while I was still under it. Luckily, the lower rocker lip on the side I was on caught the cradle of the jack stand and kept the car from crushing me. Had to manipulate the bottle jack to lift the car off myself while I was pinned under the car. I remember that day very vividly.
The moral of my long winded story is: Don't try to put a 73-77 Cutlass rear under a 68-72 Cutlass - it will not fit.
Back in the 80s I tried installing a '75 rear into my '70 Cutlass and almost killed myself. I was using a bottle jack to lift the rear into the mounts and it wouldn't go. Kept lifting with the jack to force it in, ended up lifting the entire car off the jack stands; car slipped sideways and fell off the jack stands while I was still under it. Luckily, the lower rocker lip on the side I was on caught the cradle of the jack stand and kept the car from crushing me. Had to manipulate the bottle jack to lift the car off myself while I was pinned under the car. I remember that day very vividly.
The moral of my long winded story is: Don't try to put a 73-77 Cutlass rear under a 68-72 Cutlass - it will not fit.
Registered User
Joined: Jan 2009
Posts: 5,556
From: Harrison, Michigan
The mismatch is such that you cannot install the rear into the control arm mounts.
Back in the 80s I tried installing a '75 rear into my '70 Cutlass and almost killed myself. I was using a bottle jack to lift the rear into the mounts and it wouldn't go. Kept lifting with the jack to force it in, ended up lifting the entire car off the jack stands; car slipped sideways and fell off the jack stands while I was still under it. Luckily, the lower rocker lip on the side I was on caught the cradle of the jack stand and kept the car from crushing me. Had to manipulate the bottle jack to lift the car off myself while I was pinned under the car. I remember that day very vividly.
The moral of my long winded story is: Don't try to put a 73-77 Cutlass rear under a 68-72 Cutlass - it will not fit.
Back in the 80s I tried installing a '75 rear into my '70 Cutlass and almost killed myself. I was using a bottle jack to lift the rear into the mounts and it wouldn't go. Kept lifting with the jack to force it in, ended up lifting the entire car off the jack stands; car slipped sideways and fell off the jack stands while I was still under it. Luckily, the lower rocker lip on the side I was on caught the cradle of the jack stand and kept the car from crushing me. Had to manipulate the bottle jack to lift the car off myself while I was pinned under the car. I remember that day very vividly.
The moral of my long winded story is: Don't try to put a 73-77 Cutlass rear under a 68-72 Cutlass - it will not fit.
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