Which diff to build

I want to upgrade my diff in my drag car. I have a 8-3/4” under the car now.

Dana 60
Ford 9”

Which one and why?

Ohhhhh boy here we go. Lol 😂

I have two dusters with Dana’s and one with a 9 inch. I prefer the 9 inch for ease of installation as I have extra gear sets ready to go.

Before that "OOHHH boy"" onslaught begins, tell us what you have car/motor/suspensionwise and where you are HP/ET.

I'm also onsidering a Ford 9" since myself (and other's) are struggling to find pro gears lower than a 4.10 ratio for a Dana.

Coin flip!

The 9 inch is easier to change gears and has many more gear options then the Dana but it’s really a toss up either way you will be fine over a 8 3/4

Dana 60 because it is a Mopar and the Dana 60 will last longer.
The nine inch Ford with mostly stock parts has a lot more drag and the stock parts don't live with higher HP with good traction

A Dana is a ... Dana. They just happen to have been installed in Mopars !!

77 RoadRunner tube chassis. 2750 lbs race weight. 340 W2, runs 10.0's at 132 mph. ladder bar suspension.

i want to upgrade the diff as i will be building a new engine. should run in the 9.30-40 range

Contact Cass at Dr. Diff and let him explain the difference and price.

Correct, there is a Dana 60 installed in our Iveco Van

Go with the Strange S-60.

A Dana might work for you, just depends on what gear ratio you need. These days it is probably smarter to go with a nine inch, especially if you might be selling the car down the road. I changed from a Dana 60 to a 9 inch in my Duster since I couldn't buy the correct ratio for the Dana.

And Ford trucks, Ford vans and Chevy trucks.

I have a S-60 in my Dart, if I were doing it over it would be a 9”. Look at all the options for gears and brakes.

This article about sums it up. https://www.onallcylinders.com/2018...9-pros-cons-popular-rear-end-assemblies/

About the cheapest conversion for a rear a lot stronger than an 83 /4 is ( or was) a truck dana with a clutch type posi and a ratio you can use. I found a Dana 60 with 4.10 gears. A used set of 35 spline axles , a disc brake kit, spring pads and I had a strong rear for my 535 stroker on the cheap. The posi didn't survive long but some home made shims added to the clutch pack in the diff locked it up. As I recall it only took one shim made from the end of a 3 lb coffee can to do the trick.
This was done 40 years ago so I have no clue as to what dana 60s go for at the boneyard or what posi's, or ratios are available now days.

Running a 4.10 gear I’d use the Dana 60. They are cheaper to build of you look around. You can use the brakes off your 8.75. The biggest issue is finding the gear sets like Andy said. If the gear ratio(s) you use are easy to get the D60 is a no brainer. I just had a D60 done for my car. After pricing it out to get the same thing in a 9 it was over a grand more, all else being equal. And I’ll say it again...the oft quoted saying of it’s easier to change the gear sets is just that. Very few people EVER do it the way they claim. Plus, you have the added expense of another third member. I’m a value kind of guy, not the run what everyone else does because it’s trendy. At your power level you should be able to put several hundred runs on a D60 gear set and never think about it. The one thing I didn’t do when I did my D60 was 40 spline axles and spool. I’m just kicking myself right now for not doing that.

9" with zero Ford parts involved just the engineering with the three pinion supports. I have had all three rears under my Savoy and my easy service diff was by far the 9" Got a Dana under the car now because it was almost free. BUT prefer the 9"

Gus

I have an S60 in my Duster. Have 4.30 gears and 4.56 already on spools. Really doesn’t take that long to swap gears and is certainly cheaper than a whole after market “pig” set up ready to swap. If you do go 9” do your homework on a housing that will hold up. Ladder bar kind of hard on stuff. My rear including rotors/calipers is 198lb.

My S/P car had a Mark Williams Dana 60 with his 40 spline axles and aluminum spool with a set of Pro Gear 5.87 ratio , I replace them with a new Moser 40 spline 4 series spool and a used set of Dana stock 4.56 ratio ring and pinion out of a used pick up rear end rom a junk yard. I wanted to use a set of stock Dana 4.10 gears but no one makes a 3 series 40 spline spool I can reinstalled those Pro gears by changing the rear pinion bearing shim by .003 Probably take me less than 2 hours now, I'm 76 yrs old and getting slower
The car had a all aluminum KB blown alcohol motor with B1 heads that ran 7.64 at 184+ MPH with the driver weighing under 2600 Lbs. is the story I was told.
I have a lot of runs on those used 4.56 now with a 400 stroker motor on E85, best ET so far is 8.86 at 150. MPH weighing 2850 Lbs. with me in it. No noise or problems with that dana 60 so far

Unless you have a compelling reason not to - Stock Eliminator, Mopar street car, purist, budget - 9" is always the right answer for a race car.

Gear selection, all steel housing, easier to work on, aftermarket support, lightweight parts, stronger when properly done, pinion lower in the carrier, etc.

On the street though, Mopar guys see that diff cover from the rear and they know you aint playing around. On a race car it sounds like the 9" may be the way to go.

I will need a 4.56-4.88 gear. What’s the difference in weight? So many answers on google and they all are different. Is the 9” 100 lbs lighter?

When the 9 inch is made as strong as the D60 the weight is the same or so close it doesn’t matter. The D60 at the gear ratios you want to run takes less power to drive.

Unless you need to swap gears all the time the Dana is the way to go.

Call Cass. When he broke it down for me, the choice was easy. He sells both and will be happy to build whatever you want. Also, he knows all the mopar pinon offsets and stuff that you may not get if dealing with other dealers. I purchased mine complete with his brakes. Has been trouble free for 11+ years under a 10 second B-body street car. Will likely go 9's this year.

https://www.doctordiff.com/

That ratio is available for the Dana. If you are going to be changing gears very often then you should buy a Strange S60 since they are much easier to work on. The cheapest option is to find a used Dana 60 in a wrecking yard and have a local shop cut it down and put gears and a spool in it. If it was me I'd put the Ford Torino ends on it with the Set 20 bearings so you can get rid of the Mopar adjuster. The Torino ends will give you a ton of brake options. Since it is a ladder bar car you don't need the pinion snubber mount so no need to pay extra for that. If you don't have a local truck shop or chassis builder who you trust then you might need to order it from someone.

i will call Cass next week and see what he recommends. i have bought stuff from him before and is a super nice guy to deal with.

i won't be changing gears from weekend to weekend. good chance i'll end up with a 4.56 ratio.

i was looking at the S60.

You might be able to find a used one for sale. I sold the S60 from my Duster for $1900 last month. It had 4.10 gears, Detroit Locker, 1350 forged yoke as well as Ford Explorer disc brakes. I also had a spare set of 4.56 gears and a bearing kit for sale. Complete package deal was $2100. I didn't get too much interest on it but finally sold it to a guy who was building a S10 pickup.