1966 Chevy C20 Rear Ends

[Bradfather]

Hello, I am knew to all this rebuilding so I don't know all the tricks and kits that could possibly exist. So I need a lot of help. I want to get the rear end question answered today.

I am rebuilding a 1966 Chevy C20. I have a limited slip in the rear end. I want Disc brakes and I am trying to aim for keeping the original housing. (as it bolts up to everything right!)

Is there a way to make or rebuild that rear end into a 4:10 posi 1/2 ton (5 bolt pattern) with disc brake kit or is the tubes for the axles going to be to big? (I am sure there is a kit or something out there. Like there is for everything else.)

Otherwise what would you suggest doing? Finding a different rear end maybe 71-72 C10 Posi and put that in or a Ford 9"? I am assuming a Ford 9" will be extra extra work to get that put in.

[Captainfab]

I wouldn't waste any money on that Eaton HO52/72. For one, you can not do what you are wanting to do with it. You will be far ahead to find a '71-'82 12 bolt or a '79-'87 10 bolt. Of course the '71-'72 will basically bolt in. The '73+ will require some cutting and welding to bolt into your truck. I make the trailing arm mounts, and you can cut the panhard bar mount from the Eaton and weld to the new differential. You could also use a '64-'70 12 bolt and install the 5 lug conversion axles. The '70 and earlier differentials are 1.5" narrower than the '71 and up. And of course you will have to install the posi carrier and gears that you want in which ever differential you go with. The chances of finding a differential already with a posi is somewhat slim.

[Bradfather]

The limited slip in it now is a 12 bolt but when you are saying a '64-'70 12 bolt are you referring to a different kind of 12 bolt? A posi 12 bolt? Kind of confusing. Like I said, I am dumb to the world on this stuff.

[Bradfather]

I also want to lower this truck. So I don't know if that makes a difference or not either. I am just doing the 3 or 4 inches in back and the 2.5 inch drop spindles in front. I am hoping for an even looking truck.

[Bradfather]

Will a 03-04-05 Chevy Silverado SS Rear End Differential 4:10 POSI With The BIG BRAKES work?

[Captainfab]

A '66 C20 did not come with a 12 bolt. They typically came with the Eaton HO52/72. Do you have 6 hole wheels or 8 hole wheels?

Originally Posted by Bradfather

The limited slip in it now is a 12 bolt but when you are saying a '64-'70 12 bolt are you referring to a different kind of 12 bolt? A posi 12 bolt? Kind of confusing. Like I said, I am dumb to the world on this stuff.

Originally Posted by Bradfather

I also want to lower this truck. So I don't know if that makes a difference or not either. I am just doing the 3 or 4 inches in back and the 2.5 inch drop spindles in front. I am hoping for an even looking truck.

The newer truck differential will be 3-4" wider than a 12 bolt that a '66 C10 would have originally cam with. You would definitely have to run the deep backspacing factory '03-'05 wheels. Even at that you may have clearance issues. I can not say for sure as I have never attempted to install a differential that new under a '63-'72 truck. I typically stick with a truck 12 bolt in a C10.

Originally Posted by Bradfather

Will a 03-04-05 Chevy Silverado SS Rear End Differential 4:10 POSI With The BIG BRAKES work?

[Bradfather]

Originally Posted by Captainfab

A '66 C20 did not come with a 12 bolt. They typically came with the Eaton HO52/72. Do you have 6 hole wheels or 8 hole wheels?





The newer truck differential will be 3-4" wider than a 12 bolt that a '66 C10 would have originally cam with. You would definitely have to run the deep backspacing factory '03-'05 wheels. Even at that you may have clearance issues. I can not say for sure as I have never attempted to install a differential that new under a '63-'72 truck. I typically stick with a truck 12 bolt in a C10.

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[Bradfather]

8 hole

[Captainfab]

Maybe this will help determine which differential you have.

[Bradfather]

Bottom row, first one! GM 12 bolt

[Bradfather]

Actually, I think its more rounded. but it does have 12 bolts.. here is a pic of it.

[Rust-O-Matic]

That's an Eaton HO52. My '66 has the same axle. Tough as nails, but parts are basically obsolete. I'd love to find a higher (numerically lower) set of gears and a posi unit for mine, but have never seen either for sale.

[Rust-O-Matic]

Bradfather, when you say "limited slip" do you mean "posi" which is the same thing, or "open differential" where only one wheel is powered at a time? If it's a posi I'd be interested in buying the guts of your rearend if you decide to junk it, but I'm not interested in an open differential. Already got one.

[yelmer]

they came in 2 types for 3/4 ton std is 457 open . 411 opt. open and 457 detriot Locker opt.

[Rust-O-Matic]

That heavy old axle with a Detroit locker would be tuff with two f's.

[Bradfather]

I turn one wheel and the other wheel turns the opposite way. So I don't think that's posi, correct? And is this a 12 bolt rear end? I count 12 bolts on the housing cover but someone before said it's NOT a 12 bolt. ??

Originally Posted by Rust-O-Matic

Bradfather, when you say "limited slip" do you mean "posi" which is the same thing, or "open differential" where only one wheel is powered at a time? If it's a posi I'd be interested in buying the guts of your rearend if you decide to junk it, but I'm not interested in an open differential. Already got one.

[yelmer]

that is a open rear end no locker a locker will go the same direction on both sides

[yelmer]

locker unit