Confused on which rear end to replace 7.5 with

[CartmanTD]

If you're going to buy a rear and spend big money, get a GM 12 bolt. I believe moser and Currie make one that is a direct bolt in. Best choice out there for these cars if you ask me.

 

[david lehman]

Your rear most likely has 3.42 gears, not 3.43 and while its generally not recommended you can put some power through the gbody 7.5s, but its not worth the risk even if you go all out and build them up. A 10 bolt from a 68-72 CHEVROLET a body like s Malibu/chevelle will fit but you will need custom upper and lower control arms because that rear end is about an inch or so wider on either side. UMI makes upper and lower arms that are adjustable and have heim joints to avoid binding. If you wanna keep it gm but want it to be bullet proof, get a 12 bolt from a 68-72 CHEVELLE. The BOP rear ends are different and won't fit. In short, that 10 bolt chevelle rear will work, just rebuild it first. Gears, axles, new posi unit, gaskets, bearings, etc.

 

[david lehman]

Your rear most likely has 3.42 gears, not 3.43 and while its generally not recommended you can put some power through the gbody 7.5s, but its not worth the risk even if you go all out and build them up. A 10 bolt from a 68-72 CHEVROLET a body like s Malibu/chevelle will fit but you will need custom upper and lower control arms because that rear end is about an inch or so wider on either side. UMI makes upper and lower arms that are adjustable and have heim joints to avoid binding. If you wanna keep it gm but want it to be bullet proof, get a 12 bolt from a 68-72 CHEVELLE. The BOP rear ends are different and won't fit. In short, that 10 bolt chevelle rear will work, just rebuild it first. Gears, axles, new posi unit, gaskets, bearings, etc.

 

[david lehman]

THANKS FOR YOUR ADVICE IT SOUNDS LIKE A 12 BOLT WOULD BE THE ULTIMATE CHOICE /NOW MY QUESTION IS ONLY 12 BOLT CHEVELLE REARENDS WILL WORK FROM 68 TO 72 ? WITH THE UMI AJUSTABLE CONTROL ARMS OR ARE OTHER CHEVY CARS THAT HAD 12 BOLT RE?

 

[lilbowtie]

Your probably going to have a harder time finding a 12 bolt over an 8.5 and pay more for it. I have a hard time throwing down that kind of cash (and won't) for 40 year old pieces that aren't set up the way you want. A body 8.5 rears are cheaper but still need arms and off set wheels and still 40 years old. Put pen to paper and then make your choice.

 

[MrSony]

Adding to pontiacgp's post, that's 4.5 inches total. So it's 2.25 inches on either side. Offset wheels, you were probably gonna get new wheels anyway. 40 years old, should rebuild it anyway. Never trust old parts. They will fit, just with some tweaking.

 

[565bbchevy]

I personally did not want to buy new wheels just so I could have a stronger rearend and 2.25 inches wider per side added to a 4 inch backspace you probably already have means you are looking at approx. 6 inches of backspace to keep the wheel in the wheel well and without a frame notch and going wider than an 8 inch wheel there will be very limited selection at this backspace

 

[motorheadmike]

Strange S60 - direct bolt in. 'Nuff said.

 

[GP403]

not to hijack the thread but it looks like something very strange happened and the thread title got jacked up. If anyone could LMK what its supposed to be or just post it here I'll fix it and hope its not happening to other threads (!) thx.

 

[theoldsone]

While I feel an 8.5 will work for many applications it also has it's limitations besides the fact there are only so many available and many people now think they are made of gold and price accordingly so if you plan on making enough power to require an aftermarket differential carrier, new gears and upgraded axles then basically all you are using is the housing and I think starting off with a 9" housing that is stronger and already has upgraded axles and does not require c-clip eliminators to be track legal puts you ahead at this point.
But this only applies if you require that much rear end to handle the power.

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