12 Bolt Chevy vs 8.5" 10 bolt Buick.
March 28th, 2018, 09:14 AM
#1
Registered User
Thread Starter
Join Date: Oct 2017
Location: Edmonton, AB
Posts: 19
12 Bolt Chevy vs 8.5" 10 bolt Buick.
as the title states I'm looking to upgrade the rear end of my car on a budget. I know people who own both locally and are willing to sell. The 12 bolt Chevy is 600, complete but has highway gears and an open so those will both need to be replaced. The 8.5" 10 bolt corporate Buick is 200, so cheaper initially and I will probably have an easier time finding a used carrier posi and 3.73s like I want. Both are complete and will bolt right in.
Background on the car is a 70 442 with a 455/400, probably makes 425hp/525tq at the flywheel as a rough estimate. Will be more in a year or two when I rebuild the engine.
looking for opinions on what people are running and which would be a better purchase. Thanks for the advice.
Background on the car is a 70 442 with a 455/400, probably makes 425hp/525tq at the flywheel as a rough estimate. Will be more in a year or two when I rebuild the engine.
looking for opinions on what people are running and which would be a better purchase. Thanks for the advice.
March 29th, 2018, 06:48 AM
#4
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Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,737
Rear ends
Well I would not bother with either if all your going to do is still crappy used parts in them. Sorry to be blunt, BUT you are spending money on the motor to be more powerful and the rest of the drive line needs parts too or your just calling a tow truck to pick up your motor with 425HP 525ftlbs of torque that sits in a lump of metal on the side of the road.
So really in this case it will not make a difference which one you get cause both will fail with used parts against that torque. Ok? Sorry for being a D--K but this is just facts.
NOW if you want real answer... The 12 bolt will be worth more in the long run of the cars life if built correctly(resale and such)...600.00 for a housing basically is what your spending which in my book is too much money...(even though that is the GOING rate for a open non posi rear 12 bolt )GUYS think they have GOLD or something and the reason we buy NEW MOSER HD 12 bolt Chevy housings which are superior in every way to GM original 12 bolt.
You will need a NEW posi , NEW gears, New bearings and seals, and I personally would by NEW alloy AXLE shafts as the original ones are JUNK case hardened piece.
so total your in for 1000.00 in parts and you still have to set the rear end up, 600.00 for the core and professional set-up minimum 300.00 then you have to clean the outside another 50.00 in labor from you or sand blaster. Add it up your at about 1800.00 to 2000.00. AGAIN if you buy used parts I am sure you can cut an easy 500.00 in parts and if you set-up the rear that amount in labor too. It will be no better than the rear under the car as we write.
10 bolt 8.5 200.00 for a housing is not bad...that is about the going rate...MAKE SURE it is a 10 bolt 8.5 though.
you will have about 800.00 in NEW parts reuse the bolt in axles (that is a good thing about the 8.5 71 72 rear BIA and the reason we buy NEW 12 bolt chevy axles always) all new bearings and seals, New posi , New ring and pinion. assembly same as 12 bolt - in the 300.00 range, clean the housing 50.00 ish .... so you are in the 1400.00 is usually a normal build... again you can do it on the cheap with used parts...maybe come in around 600.00 and you do the set-up yourself...BUT ... all that torque and HP will be wasted when you start mashing the pedal... might even lock the rear up and end up in a ditch...???
These are all your choices in life.... Please do not be a NEWS real at 11pm.
Good luck,
Jim
J D Race
So really in this case it will not make a difference which one you get cause both will fail with used parts against that torque. Ok? Sorry for being a D--K but this is just facts.
NOW if you want real answer... The 12 bolt will be worth more in the long run of the cars life if built correctly(resale and such)...600.00 for a housing basically is what your spending which in my book is too much money...(even though that is the GOING rate for a open non posi rear 12 bolt )GUYS think they have GOLD or something and the reason we buy NEW MOSER HD 12 bolt Chevy housings which are superior in every way to GM original 12 bolt.
You will need a NEW posi , NEW gears, New bearings and seals, and I personally would by NEW alloy AXLE shafts as the original ones are JUNK case hardened piece.
so total your in for 1000.00 in parts and you still have to set the rear end up, 600.00 for the core and professional set-up minimum 300.00 then you have to clean the outside another 50.00 in labor from you or sand blaster. Add it up your at about 1800.00 to 2000.00. AGAIN if you buy used parts I am sure you can cut an easy 500.00 in parts and if you set-up the rear that amount in labor too. It will be no better than the rear under the car as we write.
10 bolt 8.5 200.00 for a housing is not bad...that is about the going rate...MAKE SURE it is a 10 bolt 8.5 though.
you will have about 800.00 in NEW parts reuse the bolt in axles (that is a good thing about the 8.5 71 72 rear BIA and the reason we buy NEW 12 bolt chevy axles always) all new bearings and seals, New posi , New ring and pinion. assembly same as 12 bolt - in the 300.00 range, clean the housing 50.00 ish .... so you are in the 1400.00 is usually a normal build... again you can do it on the cheap with used parts...maybe come in around 600.00 and you do the set-up yourself...BUT ... all that torque and HP will be wasted when you start mashing the pedal... might even lock the rear up and end up in a ditch...???
These are all your choices in life.... Please do not be a NEWS real at 11pm.
Good luck,
Jim
J D Race
March 29th, 2018, 07:06 AM
#5
Registered User
Thread Starter
Join Date: Oct 2017
Location: Edmonton, AB
Posts: 19
thanks I appreciate the advice. I fully plan on rebuilding the rear end properly, maybe next winter but I was hoping to get the car on the road this summer and 1500 bucks is just cash I don't have at the moment. And I figured either was a better option then the 8.2" Chevy that someone had swapped in earlier.
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