Best rear end to run behind a built HEMI? D60 or...?

[hatersaurusrex]

So now that the plan for my '68 includes a K-head Hemi with twin 1050 CFM carbs - I'm thinking the stock 8 3/4 I bought from a Coronet is not an option - even if I go with an automatic.   Which leads me to the following questions:

1. Are there stronger gear sets for an 8 3/4 that will handle the torque of a built Hemi?  I'm not sure what the numbers will be but I expect it to be over 600 ft-lbs easily.   I know from off-roading that slight diffferences in gearsets can mean a huge difference in strength - for example a 4.10 vs 4.11 in some Dana axles will be quite a bit different, because the pinion has more teeth on one than the other and there's less metal there.   Is this true for Chrysler diffs?  I'm relatively dumb when it comes to anything other than Dana or AMC axles.

2. Assuming a Chrysler axle is out - where's a good place to find a D60 for this application?  I'd assume an OEM one for a B-body is rare AND expensive, so:

3. Anyone here ever had one from a pickup cut down?   Would a disc brake setup (i.e. Wilwood) still work on a truck axle or should I stick to hunting one built from a car?

Thanks in advance for any input!

[c00nhunterjoe]

Power means nothing without traction. My 400 hp 383 with "decent" traction was scattering my 8 3/4 axles. I built a dana 60 from a truck rear. If you have the tools and skills, its not hard. You buy the chrysler ends to weld on the tubes after you cut it down and then your factory or aftermarket discs bolt right on.
    I used a full floating dana 60. They are all over craigslist for 50-100 bucks. Doesnt matter what truck its out of since you are tossing all of the guts and cutting the ends off anyway

Here is my basic build- http://www.dodgecharger.com/forum/index.php/topic,113690.0.html

[Challenger340]

So now that the plan for my '68 includes a K-head Hemi with twin 1050 CFM carbs - I'm thinking the stock 8 3/4 I bought from a Coronet is not an option - even if I go with an automatic.   Which leads me to the following questions:

1. Are there stronger gear sets for an 8 3/4 that will handle the torque of a built Hemi?  I'm not sure what the numbers will be but I expect it to be over 600 ft-lbs easily.   I know from off-roading that slight diffferences in gearsets can mean a huge difference in strength - for example a 4.10 vs 4.11 in some Dana axles will be quite a bit different, because the pinion has more teeth on one than the other and there's less metal there.   Is this true for Chrysler diffs?  I'm relatively dumb when it comes to anything other than Dana or AMC axles.

2. Assuming a Chrysler axle is out - where's a good place to find a D60 for this application?  I'd assume an OEM one for a B-body is rare AND expensive, so:

3. Anyone here ever had one from a pickup cut down?   Would a disc brake setup (i.e. Wilwood) still work on a truck axle or should I stick to hunting one built from a car?

Thanks in advance for any input!

We've had guys attempt using 8 3/4's diffs behind Engines we've built, and invariably depending upon costs incurred to success attained, IMO, probably better to D60 at the start ?
I mean the 8 3/4 can be made to live.... but by the time you spend the money ? and depending upon actual tire "hook" it see's ?  'nuff said.....

[kamkuda]

You choices are really a ford 9 inch or a Dana 60.  Both can be built for the power. 
I like the strength of the Dana and they are more mopar oriented but the 9 inch allows for easier gear set changes if that matters to you.

[Ghoste]

And personally I think the Ford is over rated on its power handling capacity.  It has ENORMOUS aftermarket support but again, by the time you spend the money to get them there.  (stick a stock 9 inch behind a built high torque engine and see how strong it is)

[c00nhunterjoe]

And personally I think the Ford is over rated on its power handling capacity.  It has ENORMOUS aftermarket support but again, by the time you spend the money to get them there.  (stick a stock 9 inch behind a built high torque engine and see how strong it is)

Alot of the nhra .90 guys are swapping to the 9" vs the dana for the weight savings. By the time you add the aluminum components to the 9", she gets awful light. Alot of those cars are over 1000 hp..... now im not saying to build a 9" for your street/strip mopar because the cost to build the 9" thats in those cars is absurd, the point is simply that if you have deep enough pockets, you can build it to live behind serious hp and traction.

My vote stays with building a dana 60 out of a junkyard truck housing.

[six-tee-nine]

power and traction are 2 different things.

If you are going to run a 700 horse Hemi with 15" BFG's then there wont be a problem using your old axle since you wont have traction at all, so you'll be fine.
The minute you bolt a set of drag slicks to that axle its going to end up being fubar...

Why use anything different then what mopar used? So I say build a dana. Or buy one. Dr. Diff's pricing starts at around 2 grand.
Finding a used oem B body in OK shape will cost almost as much or even more if it turns out it needs new internals.
There was one listed in the classifieds a while ago, fully rebuild (seller stated so, what does that really mean anyway?). Asking price was 2 grand.

[Ghoste]

That's what I meant about aftermarket support, its huge for the 9 inch.  My only point was to its reputation for strength and my opinion, and its just opinion, was that the rep was built on the aftermarket support.  I also wasn't trying to imply that its weak, because it sure isn't.  I just meant that if you went to a wrecking yard and stuck one in that you pulled out of an old station wagon or something it might not be the superstar you hope.
But then again it might.

[c00nhunterjoe]

That's what I meant about aftermarket support, its huge for the 9 inch.  My only point was to its reputation for strength and my opinion, and its just opinion, was that the rep was built on the aftermarket support.  I also wasn't trying to imply that its weak, because it sure isn't.  I just meant that if you went to wrecking yard and stuck one in that you pulled out of an old station wagon or something it might not be superstar you hope.
But then again it might.

lol, station wagon bandit.. i'll drink to that!

Dollar for dollar, you surely cant beat building a dana 60. I think strange sells their bulletprrof s60 for around 2k. If you have the skillset to do it yourself, it can be done alot cheaper. But if you try to rebuild an 8 3/4 to be beefy, you will pretty much have the same cost as the dana, and the dana is far superior in strength.

[moparnation74]

That's what I meant about aftermarket support, its huge for the 9 inch.  My only point was to its reputation for strength and my opinion, and its just opinion, was that the rep was built on the aftermarket support.  I also wasn't trying to imply that its weak, because it sure isn't.  I just meant that if you went to wrecking yard and stuck one in that you pulled out of an old station wagon or something it might not be superstar you hope.
But then again it might.

lol, station wagon bandit.. i'll drink to that!

Dollar for dollar, you surely cant beat building a dana 60. I think strange sells their bulletprrof s60 for around 2k. If you have the skillset to do it yourself, it can be done alot cheaper. But if you try to rebuild an 8 3/4 to be beefy, you will pretty much have the same cost as the dana, and the dana is far superior in strength.

:iagree:Well stated!

[Mike DC]

                                                      
The Dana is stupid-strong but it weighs around 250 lbs - not doing anything good for the ride quality.  It has no gearsets taller than 3.54 (in the normal case).

The 8.75" is likely the lightest & lowest-friction-running of the bunch.  Aftermarket makes it strong but it's not cheap that way.  It's more like 200 lbs.

The Ford 9" is decent on weight & power and has lots of aftermarket.  The gear mesh pattern makes it inherently strong for the weight but it also makes it run hotter & parasitically drag off a few HP.  (Notice the NASCAR guys have to run fluid pumps/coolers on them at 200mph.)  I agree with Ghoste, the aftermarket built the reputation.  


The Dana is probably the strongest right out of the junkyard.  The Ford or 8.75" . . . how much money you wanna throw at it?  

[hatersaurusrex]

Great info - I figured a truck axle would make the most sense.  A couple of followup questions now that I've done more research?

Some googling shows that a 68 b-body 60 would have a 7290 style yoke  - my '68 is a big-block car (383) but I haven't looked at the driveshaft - is it going to be a 1330 or a 7290 style on the driveshaft?

The trans yoke doesn't matter so much since I can order whatever output yoke I need with my new trans, but I'm wondering if I'll need a new driveshaft as well (if it has the smaller 1330 style joints).  I think with all that torque I'd much rather have 7290's on both ends, but don't know what's in there stock without getting under there and measuring.

If I do need a new driveshaft - reccomendations?

[firefighter3931]

The D60 is definitely the best choice for your application. 

I would order an aftermarket unit with 35 spline axles and a locker unit. That's what I have behind my 572 stroker and it works fine on the street & track.

Yes, the stock driveshaft will need replacing. I'd look at a 3.5in chrome moly steel piece with 1350 yokes at both ends. Mine was made by Victory driveshafts.

Once this is all in place you will have a bullet proof driveline 


Ron

[Rolling_Thunder]

The D60 is a great axle...         However, I've ran 8 3/4s with stock axles behind really high horsepower stuff without issues....   

[hatersaurusrex]

The D60 is definitely the best choice for your application. 

I would order an aftermarket unit with 35 spline axles and a locker unit. That's what I have behind my 572 stroker and it works fine on the street & track.

Yes, the stock driveshaft will need replacing. I'd look at a 3.5in chrome moly steel piece with 1350 yokes at both ends. Mine was made by Victory driveshafts.

Once this is all in place you will have a bullet proof driveline 


Ron

What type of locker do you run?  Lunchbox, Eaton/Detroit style, Lock-Right style or....?

Anyone run an e-locker before?  They're big in the off-road world if you don't want to stay locked all the time... but seem a bit less useful for street applications - unless you're driving in the wet and don't want that little tug of resistance as the locker unloads when turning.

[kamkuda]

I run a detroit locker in my road runner with a Dana 60.  Runs great on the street.  The car is really load so I don't know if it really clicks around corners.  I doesn't seem to.