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Discussion Starter #1
What do y'all think about the S-10 / S-15 4X4 8.5 rear ends? I have heard they are a pretty strong rear end & can take abuse. They are easy to find in any junk yard & are cheap & have a perfect track width. Also can find them with these ring gears, here are the RPO codes found in the glove compartment....

GU1 : AXLE REAR, 2.41 RATIO
GU2 : AXLE REAR, 2.73 RATIO
GU4 : AXLE REAR, 3.08 RATIO
GU5 : AXLE REAR, 3.23 RATIO
GU6 : AXLE REAR, 3.42 RATIO
GV1 : AXLE REAR, 2.73 RATIO
GV2 : AXLE REAR, 5.83 RATIO
GV3 : AXLE REAR, 3.08 RATIO
GV4 : AXLE REAR, 3.36 RATIO
GV5 : AXLE REAR, 3.55 RATIO
GV7 : AXLE REAR, 4.11 RATIO
GV8 : AXLE REAR, 2.72 RATIO
GW2 : AXLE REAR, 2.56 RATIO
GW3 : AXLE REAR, 2.56 RATIO
GW4 : AXLE REAR, 3.31 RATIO
GW5 : AXLE REAR, 2.73 RATIO
GW6 : AXLE REAR, 3.27 RATIO
GW8 : AXLE REAR, 4.10 RATIO
GW9 : AXLE REAR, 2.93 RATIO (DUP WITH GU3)
G80 : AXLE POSITRACTION, LIMITED SLIP
 

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They are pretty decent rearends for a street vehicle, but wont stand a lot of abuse from high HP engines. They aren't 8.5" though, they're 7.7" 10 bolt rearends. The 8.5 10 bolt was used on most '70's GM vehicles.
 

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Like Rich said, "use them in light vehicles". i know guys that have broken them in S10's w/4.3's and automatics. I believe the Explorer rear is the better choice, availability is basically the same, and will handle more abuse. And requires about the same amount of work to install.
I know that wallet and skill will determine what rear you end up with. Just keep in mind what rear you chose when you go to flat shift second gear...
 

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Discussion Starter #5 (Edited)
They are pretty decent rearends for a street vehicle, but wont stand a lot of abuse from high HP engines. They aren't 8.5" though, they're 7.7" 10 bolt rearends. The 8.5 10 bolt was used on most '70's GM vehicles.
I have read there are different versions of the 10 bolt rear end, 7.5", 7.8" & 8.5". I need to measure the hub to hub width on the rear end thats on my '53. I would like to go with a Ford 9" but I think it will be hard to find one the right width in my price range thats why I'm starting to look into the 10 & 12 bolts. I just thought the S-10 rear end was a good choice from what I've been reading cuz they are cheap & easy to find.
 

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Yes, there are numerous versions of the Chev 10 bolt, and some are very strong units. They made them in 7.7", 8.2", and 8.5" All the S10 rearends are the small 7.7", and are the lightest duty. They've been used in hundreds of hotrods, and depending on how they're driven they do sometimes last quite well. I know a guy who's running a V8 swap in his S10 with a stock rear for years, so some do work.
The 8.2 were used a lot in Chevelles, Novas, and Camaros in the '60's, but they were replaced by the 8.5 in 1969-70 period. They had a short run, and were noted for being about as strong as the 7.7", and OK, but not for serious power.
The 8.5" is only 1/4" smaller than the highly touted 12 bolt, and it's been installed behind some high HP engines, and held up well for street use. It has it's weak points, (the axles) but with good axles and a outboard bearing kit it will hold up to almost anything a 12 bolt will handle. I broke 2 of them when I drag raced my '71 Camaro, but once I built my present 8.5 that I removed from a '78 T/A Firebird, it's held up for 20 yrs. with no problem.
If you do decide to go with a 7.7", I would not race the car, and I'd recommend getting a good pair of axles. The axles are usually what gives out long before the ring & pinion do. New axles and an outboard bearing kit will run around $550, and a S10 rearend is around $150. Might save some over a 12 bolt or 9" Ford that's set up right, but wont hold what they hold stock.
The rear in my Austin is some GM Canadian halfbreed 10 bolt that's got monster sized axles that are larger than most 10 bolts or 12 bolts I've seen. The carrier is some weird thing that's the same as the 8.2" GM, but drilled to accept 7.7" ring and pinion. Gave us fits when I was trying to find parts to assemble lower gears, and I hope it continues to hold up, as I don't want to spend what it costs to have one custom built. If it doers ever crap out, I'll probably bite the bullet and go 9" Ford though.
 

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Not trying to sway you one way or another but `66 to `77 ford broncos all used `58 inch wheel flange to wheel flange rear axle widths on their ford 9 inch a few were eight inch but not many, if you hapen to run across one grab it, most all were large bearing axle housings, 28 ad 31 spline if you find a complete unit.
 

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Not trying to sway you one way or another but `66 to `77 ford broncos all used `58 inch wheel flange to wheel flange rear axle widths on their ford 9 inch a few were eight inch but not many, if you hapen to run across one grab it, most all were large bearing axle housings, 28 ad 31 spline if you find a complete unit.
That's an excellent choice if you can find one. A buddy of mine has been running one in his '68 Camaro for 10 years now behind a "mild" 454 with a trans brake.
 

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Discussion Starter #9
I'll defintely keep my eye's peeled for one. Sounds like an excellent choice.
 

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Hey guys, a nice option as well is the ford explorer rearend. 60" axle flange to flange (same as 67-69 camaro and 68-74 nova) 8.8" ring gear, 31 spline non tapering axles, same pinion diameter as a 12 bolt, I would say 70% are 3.73 posi, 95 and up are disc brakes with integral drum parking brakes, and I buy them for $120 as many as I want. Some have 4.10s or 3.27s as well.
 

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Alhough it is a good rear axle the problem arises with its 2.5 inch pinion offset, if its used for hard launches they tend to break, (housing ) if you center it by cutting the long side of the housing keep in mind the tubes are a lot thinner than the early 9 inch and warp easily.
 

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Discussion Starter #12 (Edited)
What about a 67-68 Firebird rearend, well thats what the add says.....is it a 10 bolt, wonder what the hub to hub measurement is? Found it forsale for $90.
Also found 82 Granada 9in for $330
 

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Are you building your car to race? Are you using tires with grip? (. Drag tires). If it's a street car instead it makes a difference in what you could use. Most cars that have a 9" rear will never turn the tires. Remember that there are several 9 and 10 second Buick Grand Nationals with 10 bolt rears.

Run what you can afford.

Mike
 

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I have a 9" out of a ford truck. By the time I get it narrowed, have the axles resplined ( if they can be) and get gears and a locker I will probably have about 750 in this thing. I have really been leaning toward the explorer rearend lately. If I could find one with a limited slip I would only have to buy the gears.
 

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Because of the shape of a spline it's fairly easy for shops to reharden them and get decent penetration. Dutchman's here in Portland resplines and hardens them all the time and they seem to hold up. I've got Dutchmans axles in my '71 Camaro and my Austin.
 

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I would like to go with a Ford 9" but I think it will be hard to find one the right width in my price range thats why I'm starting to look into the 10 & 12 bolts.
You're likely to pay double (if not triple) for a 12 bolt than you will for a 9 inch. Unless it's a truck 12 bolt (which is different than a car 12 bolt), but it'll probably be too wide for you.
 

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My friend is building a '36 Plymouth coupe gasser, and just bought a 9" rearne dfrom the local wrecking yard from a late 60's full sized Ford for under $200. Still needs to have it narrowed and put either a complete carrier, or get gears and posi for the existing carrier. Buidling up rear axles for cars that need narrowing gets really spendy.
 
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