8 3/4 vs. Dana 60

I moved over from the previous discussion on upgrades because I do see that before I move on with adding power I need to assure the rear end is ready for it. The Tremec is supposed to be good for 600 hp so we’re plenty good there. The 8 1/4 has endured what I have thrown at it so far but I am going on the experience of others about its limits.

So of course the 8 3/4 and Dana 60 were thrown out there. I am well aware of the capability of the 8 3/4 and am familiar with the set up and adding disc brakes to it. For me, straight forward.

But the Dana I thought was too much rotating mass and may be an overkill for a small block at even 450 hp with a manual trans.

How available are the right housings and center sections (3.91 gear with ls) going to be for each type? (Going in a third gen b-body) Is there going to be a difference in the cost to build each one? Is there a wow factor with the Dana over the Chrysler unit? Besides strength or longevity will one perform better than another in different situations such as street, auto cross and 1/4 mile? Will narrowing one be easier than the other?

If I have not mentioned something that should be mentioned please bring it up. Thanks!

I will say there was a reason Hemi and 440 manual shift cars came with Dana 60s.

I will also say that from personal experience the higher efficiency of the Dana makes up for the increased weight and your car will as fast with either the Dana or the 8.75.

As far as the wow factor, I think anyone that looked under you car and saw a Dana would think it was a more serious effort than if they saw a 8.75

For 450 HP I sure wouldn't spend the money on a Dana. And the "wow factor" is not that big of a deal either. 8-3/4's are a dime a dozen and readily available. They can be shortened just as easily as any other rear end. They're also significantly lighter than a Dana.

I am not saying that he probably could be okay with an 8.75 for a long time but to one of my earlier points, how much HP did a stock 440 manual shift car have back in the day? Did they all not come with Dana 60s?

For anything with slicks and maybe 450HP or so, and especially a heavy car, I'd think Dana.
For a stick car on slicks, I'd think it pretty much mandatory.
For a street car, I wouldn't.
I've built several cars along those lines and haven't broken anything.

I've shucked 8 3/4 ring and pinions with a 383 4spd. maybe an 8 3/4 will hold up; maybe not. a lot of factors to consider. if you do an 8 3/4 and rip it the initial cost and repairs will be more than the initial cost of a dana.

One detail not mentioned, is current tire and/or future tire choice.

I would think an 8.75 would handle anything a 8.25 is currently handling.

There is one upgrade to the 8.75 I would suggest other then well assembled with quality R&P, are upgraded cap(S). a rear brace IMO does little to promote 8.75 member longevity, but it does stiffen the housing, which if that is an issue, you are already in Dana country.

Based on what you shared so far, my choice confidently would be the 8.75.

The key metrics here are IMO, car weight, engine torgue, transmission, tire package, future possible upgrades, and intended use.

If you need it, I have the stock 1971 8-3/4" housing and axle shafts from my '71 Charger. I sold the center section.
Not sure what shipping would cost?
I seemed to hold up fine running mid 12's, but the limited slip started making noise when I got into the 11's, so I put a Strange S-60 in with a spool.

Same here, I've toasted quite a few 8 3/4 rears, even behind a few 340/4spds's..... DANA 60, end of story

I’m running a 9.25 behind around 450hp/600tq. I re-set endplay with a crush sleeve eliminator, added new upgraded yukon axles, and made sure it would stop well and retain the axles in case of a C-clip failure with jeep JZ disc brakes. I also went with a forged 1350 pinion yoke. I have about $700ish in it total and I have high hopes for a long life on the street with occasional 1/4 mile passes. I also went with a cast aluminum diff cover with bearing saddle supports. That part is mostly bling even though you’ll never see it under my lowered truck but discs and finned aluminum sure looks like more $ than I spent.

THIS ^^^^^^^^

That 9-1/4 is also a good inexpensive alternative.

Build a Dana and you're done. Building a dana from a junkyard truck rear can be done cheap. Especially if you get one w/ the good track-lock diff. It'll have either 3.54 or 4.10s gears in it already most likely.
The one I put in my dad's road runner came from under an old dodge motorhome/camper van of some sort. Had the good track lock diff and 3.54s w/ a 1350 yoke surprisingly. All we did was narrow it, weld on pass. car ends and perches, and get some 35 spline axles from Dr. Diff. As well as his track-lock rebuild kit w/ the 35 spline side gears.

Backbraces and billet caps for an 8.75 are "feel good" parts. May make you feel better, but do nothing to keep it from shredding the ring and pinion.

what is the car being used for? If you aren't frag racing dropping the hammer at 6k the 8.75 will be fine. If it makes you feel safer back brace it. Looks like a road racing car, a dana adds weight. My old 440-6 Charger went 11.20's @ 121+ had a 8.75 and 3.91's no issues at all. That was much more than 450...not too mention the added torque of a 440.

Well it’s a car that is a “jack of all trades and a master of none”. It has a full interior and tips the scale at 3900 lbs. Once a year on the strip and once on an auto cross. Never slicks. Has to be suited for out of state road trips. It is not shown at car shows but frequents regional cruise ins. It sometimes gets hammered pretty good on the streets when the coast is clear. It needs to gain the respect of serious car people whether at Mopar events, the Hot Rod Power Tour or Good Guys.

The hp and tq of the current small block will be increased to the goal of 450 for each power measurement hopefully after the rear end improvement. I am slow about making improvements since it is just a hobby but I will spend a little more dough to make the improvement the right one and not cheap out.

Except the end result of a failed cap is, a "shredded ring and pinion".

3900 lbs and manual trans will not be the issue. UNLESS its spends a lot of time on the drag strip

its when you pop a set of slicks on it and drop the hammer is when it will be testing the 8-3/4 's limits

for me personally it would come down to gear choices. And theres not much for the Dana in something street / hiway friendly
But with an OD trans and a set of 3.54';s may not be bad for longer drives

Dr Diff has 3.23 for the D60

That is one of the best ways to save time, effort and money Some people never learn this
Do it correctly ,ONCE

The 3.55s in the 8.25 now are a bit too long. They were great with a 42RE I had in the car earlier but with the Tremec 70 mph and it’s only turning 1800 rpm. With the small block I have to wind it up to about 2000 rpm to leave from a stop light and not have to wait for the engine to take forever to catch up in order to shift to second. If that makes any sense.

I had a Tremec six speed with 4.10s in another car that was great. That’s why I think 3.91s would be a good gear with this five speed.

Can 3.91s be found for a Dana?

I build lots of rears in my little one man shop. Parts are expensive so you only want to do this once. Getting used parts is a crap shoot. Building a Dana from a truck can be done but it is time consuming and can be done wrong. I’ve got a Dana in the shop right now that was not set up properly but it was still working. I would hate to have bought it as a good unit then opened it up to have to rebuild it. I don’t like spending money twice. They are one tough rear end, though. I’ve had plenty of 8 3/4 that have not faired that well even with street use. The rear end you need is for a 71 up b body and is a little more difficult to find in any form but an oem Dana is kinda rare. But not in high demand like an ebody so they don’t bring the ebody price tag with it. HOWEVER, I just happen to have something that might interest you. It’s an original 72 b body Dana 60 that has not been modified. As a matter of fact, it has been completely restored. I got it in parts deal so I don’t have the big dollars in it that the original purchaser did. It has everything new, axles brakes, sure grip, 3.54 gears and even powder coated. It was built by DoctorDiff. It is a first class unit and ready to bolt in. If you are interested, PM me and we can talk.

I can't tell you what better suits your car, but I can share what it cost me to build a Dana.

Got one off of Craigslist that was pulled from an 83 F250. All in it was about $2600 with all new parts except the ring and pinion and included disc brakes.

Almost identical to my experience. Cut down Dana 60 from a truck, welded on car ends and used a spool and Dr. Diff axles. Under $1k total and ran identical to what the 8 3/4 did the week prior. I run 3.54's.

A lot will depend on how the car is used also. I can tell you this that I bracket raced a 340 Dart back in the late 70's and early 80's. It was a 4-speed car and ran low 12's with a best ever et of 11.94 @ 113. Now when I launch a 4-speed car the gas pedal goes to the floor when the clutch comes out. In 4 years of racing the Dart I broke at least three 8-3/4 rears. Tore all the teeth of the ring gear once. Broke the pinion teeth once and broke the carrier once. Now fast forward to today and I have my 63 Sport Fury with the 8-3/4 rear in a heavier car. But my 63 is a 727 auto car. Its run 10.70's and it has never broke the 8-3/4 in it. I only race it about twice a year but its been on the road and raced some since 2011. The stick shift driveline is much harder on the rear if you run the car hard since it shocks the drivetrain. With an auto street car and street tires that don't hook the 8-3/4 should hold up fine. But with stickies it will depend and with a stick car it will be even worse. Ron

The gear fails first, resulting in the broken cap. The pinion deflects.

Always?

If so, That means an upgraded Cap mod is essentially worthless?

Wonder if the OEM cap flexes at all, facilitating less then ideal R&P teeth loading, leading to their failure.

If somebody gives you an 8-3/4 for free, go with it. If you are going to have to spend money, it's a Mopar, it looks better with a Dana under it.

I couldn't get 3.91s for my S60 from Strange about 2 years ago. Talking with Strange and Dr. Diff, 3.91s are not available from most (or all?) gear manufacturers for the Dana 60 / S60. I heard that some 3.91s out there are not cut correctly and will at the very least exhibit excessive noise. I wanted to upgrade from a 3.73 8-3/4 in my e-body to a Dana and ended up settling for the 3.73s because I thought the 4.10s would be too steep. I rest well at night knowing the S60 can take anything I throw at it drag racing with a big block 4-speed.

8.75 will be fine. Better yet save some money and get a Furd 9"

I was given this today. If I could get a housing for $100 would it be a good build to spend the money on good content and run it on the street? Sure grip, 3.91 and disc brake conversion.

Inside

Starting with a clean sheet of paper I would go with a 9" with NO FORD PARTS at all. Get a strong nodular center section from Strange and a Daytona pinion support and you will be fine with 35 spline axles and 4 pinion clutch style differential unit.

Gus

[quote=fourgearsavoy]Starting with a clean sheet of paper I would go with a 9" with NO FORD PARTS at all. Get a strong nodular center section from Strange and a Daytona pinion support and you will be fine with 35 spline axles and 4 pinion clutch style differential unit.



This is what the guys running in the 3's run. Next time at a big meet, look and see if I made that up. Actually, you won't see a Dana in those pits, anywhere.

I went that way a long time ago and I am still glad I did. Well, something else to ponder.

I run a Dana but if I was in a class where frequent gear changes were required I would certainly run something different.

A Dana looks good under anything. Here’s my S60 3.73 gears and a Detroit Locker in my Dart. It’s behind a Passon 5 speed trans.

Dude how nice is that! There are several nice upgrades within the camera lens. Is all that necessary or did you do it just because you wanted too?

Thank you. It's probably not necessary. I mini tubbed and did a spring relocation. Decided on a fuel cell and cut the trunk out and formed a box to hold the cell. Disc brakes are not needed but I wanted them. I made the hard lines, and used off the shelf DOT Russell soft lines going to the calipers. The suspension is Bill's RMS Street Linx, an older setup I bought 10 years ago when I started working on the car. I didn't like the bolt on brackets on the axle, so I ordered a weld on version from him, just to clean it up. When I put a Dana under my other car, (68 Fastback) I'm gonna stick with leaf springs. Seems to make things less complicated. LOL