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
 
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.
 
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