Rear end advice for racing with a 4 speed

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I have the dump truck rear in my Duster (Strange S60). I like the strange over the OE as it has side adjusters instead of fighting shims. I’ve got 4.56 and my 4.30 gears set up on spools and with the shim packs for the pinions it really doesn’t take that long to swap. I also have 4.88 and 5.30s but not set up. To be honest…. If I were to do it today it’d be a 9” style. I say style because none of it would be factory ford. We started having issues with the 8.75 when we started running 10s. Got rid of it all and stopped the bleeding. I will say the S60 has been rock solid and my .02$ is that the op is going in the correct direction on upgrading.
 
The Dana 60 will serve you well, after scattering a few 8 3/4 rears I went to the Dana. My car is race only, leaving at about 4000-4200 off the transbrake. I put 35 spline gun drilled axles in mine with a spool and have never looked back.
 
find a dana 60 from a 67 to 72 ford 1/2 ton pickup, its the lightest, diff in wgt is 35 lbs, it has passenger car ends , weld case to tubes with stainless rod, mine has been in my car since 1992, it has bout 3000 runs on it. just food for thought
 
reason is sst rod will weld to cast and steel, rods like 6011 will not weld to cast. just food for thought
 
19DART66 said:
Put a Dana 60 in it with a good Power Loc sure grip (not a trac Loc diff) and a good set of axles and never worry about it again.
I have a Dana out of a 3/4 ton Dodge truck narrowed to fit my Dart, it has the 1/4 inch thick axle tubes (a lot heavier than the car axles) and didn't lose any E.T. at all when I switched from the 8 3/4.
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60's and early 70's had the thicker tubs on the Dana's, after that, they thinned up. I use the 489, tapered rear end in my 69' 340 Swinger, 4 speed, that is a little stronger than the other two 8 3/4's. Remember, using the truck or van Dana's, you also need to get rid of the 8 bolt safety axles and install the 5 bolts. I believe the Dana's without the center 8 bolts are the thin ones. These rears (truck and vans) also will fit the "B" bodies. Only a half inch difference. The spring blocks need to be moved, if I remember correctly.
 
If you want a definitive answer, take a look at what the factory did with all the high horse power big block four speed cars. Dana 60.
 
72bluNblu said:
Adding a Dana will not hurt handling or street manners.

These cars are all nose heavy in stock trim or anything close to it, and better balance improves handling far more than a small increase in overall weight will hurt it. If anything the Dana will improve F/R weight bias and may even lower the CG a smidge.

There’s a small increase in driveline losses, but that would hardly be noticeable, if noticeable at all, on the street.
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I was just about to post the same . I am thinking o going to a Dana as it will improve the F/R balance and no more worries about broken diff if I hook up . Already broke 3 8 3/4
 
PROSTOCKTOM said:
340MPR said:
Hey guys,

I just got into drag racing my 69 dart last year broke my first parts, the rear end crapped out on me. My car has a 340 that makes 440HP at the crank, 4 speed, 741 case 8-3/4 rear end with 3.91’s, Mickey Thompson ET Street SS tires. After taking the rear end apart I found that the drivers side axle splines twisted and the inner side gears of my sure grip were wiped along with that portion of both axle splines, the outer side gears were fine. To get the car back in action and to make the last race of the season I rebuilt the sure grip with new, one piece side gears, new clutch plates, and found an old pair of factory axles. The ‘66 dated ring and pinion looked to be in good shape and I left them as is.

The last race of the the season was just this past weekend and I raced without issue and now I want to properly come up with a game plan. A lot of the local mopar guy’s think that the 8-3/4 will do just fine for my power level and that I should just get a new pair of axles and keep running it. I will say that they all run automatic’s and aren’t racing a 4-speed. I talked with Dr Diff and Cass figures if I’ve twisted axle splines than it will happen again, even with new axles so he’s leaning me towards a dana60.

I made around 50 passes last year and about the same this year and I’m hoping to keep that pace up. Down the road I’ll probably get slicks for the car and maybe coax some more power out of the car but nothing too drastic. It’s a true street/strip car.

I appreciate any advice from guys who race 4 speeds, thanks. Mike N

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If want to save yourself a lot of time and money put a Dana 60 or 9" Ford in there with 35-spline axles and you'll never have to think about issues again.

Tom
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Dana 60, set it and forget it.
 
Cranky said:
Get one of those TA covers with the cap supports in it for the 60. They are somewhat expensive new but used ones ain't bad...

Ain't much difference but when ounces count, so does every bit of power robbers.

Can't drive em in town like you do a reg diff but once you learn a couple of tricks, it really isn't a big deal.

Many think that a 9 is much stronger than the 8 3/4.....well, although it is stronger, it isn't that much. Imo, they do not hold a candle to the 9 3/4 (60). Lots of people like the drop out but for those that set up their own gears, you can swap gears in a Dana fairly quickly too if you save the shim package and keep them with the gear set you just removed. That way if you want to go back to them later, it's fairly easy and quick.
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You can buy parts to make a 9 inch WAY stronger than a Dana. Fact.
And the cost would be similar if talking S60 and such a 9 inch.
 
B3422w5 said:
You can buy parts to make a 9 inch WAY stronger than a Dana. Fact.
And the cost would be similar if talking S60 and such a 9 inch.
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when it was time to upgrade my car, i was debating between S60 and 9''. i ended up going with a 9'' for those reasons you mentioned.
 
AJ/FormS said:
I got about the same power, but I don't race. Well one day I did, back in 2004. I made 4 passes on an old airport runway, no prep. Car went 93 in the Eighth.

My axles are Resplined C-body axles, in a narrowed rear; I don't have your kind of problems.
I gotta get me a pair of those tires!
What else are you running back there?
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I've twisted the splines on 8 3/4 reworked truck axles (cut and splined at Mosier) I thought it was the spool. 10” Hoosiers. I would think someone offers a quality axle. Running an 833 with sintered copper clutch behind my 365 ci La.
 
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Illahe said:
I've twisted the splines on 8 3/4 reworked truck axles (cut and splined at Mosier) I thought it was the spool. 10” Hoosiers. I would think someone offers a quality axle. Running an 833 with sintered copper clutch behind my 365 ci La.
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Stock axles have to be annealed (softened) before they can be re-
splined. Then you have to depend on how well they get re-hardened.
I twisted splines bad in the narrowed re-splined 8 3/4 I had in my V8 vega..... with a weak 327, turbo 350, and STREET tires. Probably 300 hp to the wheels. Maybe.
My axles clearly did not get re-hardened properly.
If you are gonna try to make an 8 3/4 live behind ANY kind of stick, I think good alloy axles should be the FIRST mod.
 
I believe you have a good point about hardening the axle after re-splining them. I’ve never understood the concept of these cut to fit axles that are sold on the Internet.
 
Illahe said:
I believe you have a good point about hardening the axle after re-splining them. I’ve never understood the concept of these cut to fit axles that are sold on the Internet.
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My guess is that you will need an abrasive blade chop saw to cut em down, cause they have to be hard. A hacksaw or band saw ain't gonna get it done.
 
33IMP said:
My guess is that you will need an abrasive blade chop saw to cut em down, cause they have to be hard. A hacksaw or band saw ain't gonna get it done.
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That goes without saying, yet when abrasive blades are used to cut they create heat annealing the surface area within the heat affected zone.

Next time I narrow an 8 3/4 I'd prefer to order custom axles from Mosier.
 
Illahe said:
That goes without saying, yet when abrasive blades are used to cut they create heat annealing the surface area within the heat affected zone.

Next time I narrow an 8 3/4 I'd prefer to order custom axles from Mosier.
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I've got two narrowed nines, one with Strange axles, one with Summers bros.
I would not build a narrowed rear without good custom axles.
 
I would build a ford explorer 8.8. 31 splined, disk brake, they hold up to abuse. You can build one for less than $200 bucks.

Here’s my list in order of strength price wise I would argue the 8.75” is the most expensive to find, build, hardest to source parts from aftermarket.

1. Dana 60 strongest axle shafts 1.46” dia.
2. 9” strong/well supported parts axle shafts 1.33” dia.
3. 8.8 plenty strong/well supported parts cheapest to build axles are 1.29” dia.
4. 83/4” overpriced IMO. 1.25” shafts seen to many twisted axles for me to believe they hold up to abuse. Hell UTG destroyed his 83/4 with his 250hp 4 speed bottle rocket. Hehe! You also have to be mindful of the different carriers and pinion gear sizes.
 
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I like the 8.8. If I ever get the 454 in my sedan delivery, I'm gonna use one.
But there are 10" r&p sets for nine inch, and huge axles available for fabbed housing nines. There is lots of strength available for a nine.
The problem is its all expensive aftermarket stuff. A truck Dana is already strong, narrow it, good axles and fly it.
And I think most Mopar guys would rather see a Dana under a Mopar, than ANY Ford rear.
 
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I agree I have a Dana 60 shortened up 456 gears and spool for whenever I decided to build my race car, I have a moser 83/4” just a braced housing I’ve been wanting to build but can’t find cheap deals for a center section. My street car has a 8.8 under now, I shorten/built myself so cheap it’s a no brainer for me.
 
Even if you had $400 in your 8.8, it's still WAY cheaper than anything else with comparable strength and parts availability. A-body 8 3/4, Dana, nine, 12 bolt, probably all approaching or over $2000.
I bought an aluminum center for my nine inch, with a spool (lighter and cheaper than a lsd) and even on a 40% or more off black friday sale, it ran a bit over $600 (and that was cheap!).
Good axles, aftermarket discs, braced housing, I doubt very much I would take $1500 for my rearend.
 
I paid $150 for this 8.8 housing, originally from a Crown Vic. Lighter than the Explorer version, heavier than the easy to bend Mustang version, good compromise with 3" axle tubes. Cut the brackets/ears off it, narrowed it to 51-1/2" with some used 9" "Big Ford" ends I had laying on the shelf. Installed a new $700 31spl TruTrac, some used $00 Explorer 3.55's, plugged in some $500 cut-to-fit 9" circle track axles/bearings/lugs. Paid $40 for some spun Wilwood hats, $110 for a set of Wilwood rotors, used the same 4 piston Wilwoods that were already on the car. So basically $1500 total in parts.

Here's the 8.8 mocked up on the floor with a torque arm...

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Here it is in the car with brackets added...

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Ready to roll...

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Before this, the car had a 10 bolt GM rear. Ran mid/upper 5's with 1.30 60's as far back as 2011 on some 28spl c-clip axles. Manual trans car, but the axles lived because it had a 'tamer on the clutch. Those 28spl axles never failed, but one did bend last year...

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I don't think the 8.8 would have faired much better :)

Grant
 
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