Ouchy. Now what?

[INSIDIOUS '86]

So now i need a rebuild of the ten bolt. Or go with a mopar 8-3/4 diff

Question is if i rebuilf the ten bolt in my truck. I want to get bigger axles not the 28 spline. I want a locker type diff with 373 gears and c clip eliminators. If i do all this it would prob be the same cost as the dodge rear and im willing to bet money only half as strong. What would you guys do? I WILL NOT GO NEAR FORD 9'S. The dodge rear is still stronger

Anybody here do a dodge rear?
Posted via Mobile Device

[thesickc10]

go 12 bolt. 12 truck rears go for cheap and you wont break one of those.

[INSIDIOUS '86]

The 12 bolt rear is still weak. If i go 12 bolt im just going to call moser
Posted via Mobile Device

[mopar346]

I run a number of 8 3/4s all in cars though. I would go 12 bolt with a Detroit or Auburn. OR depending on the use go 60 and replace the flanges and axles, you wont break a 60. Not sure about the spring perch measurements but a semi float 14 bolt is a good choice if you repace the factory gov-lock units and it's 6 bolt.

By the way, I would not waste any money on a 10 bolt, it will cost as much as a much stronger unit. If I needed to I might throw a stock used on unit it to get by.

[andrewmp6]

I would go 14 bolt or a 9 inch if it was me.

[WarBeard]

14 bolt SF with 5 lug axle's

[Firebirdjones]

The problem with the 12 bolt truck rearend (even though I still use one in the blazer) is the small pinion diameter (1.438) I've snapped them before.

This is where the 8.5" 10 bolt you broke has an advantage with it's larger 1.625 pinion (like a passenger car 12 bolt). Honestly for all intensive purposes the 8.5" 10 bolt is a decent piece and better than a truck 12 bolt (that small pinion turns me off). The 8.5's later received 30 spline axles around the 1988 model year. Since it appears you need a 3rd member then a 30 spline axle upgrade is cake From that point on they are nearly as strong as a 12 bolt "passenger car" rear with the only difference being a smaller ring gear diameter and that's not by much, and it will be stronger than a "truck" 12 bolt.

The 8.5 10 bolts can be built strong, Dave Henninger showed everyone that when his camaro ran mid 8's at 160mph on one of those for several years.


The 8 3/4 chrysler rear has it's good and bad points too. First of all, I'd only run one if you have the 742 case with the larger pinion (1.75") or the 489 case with a 1.88" pinion. If you have the 741 case with a 1.38" pinion,,,then forget it. Start looking for a better case. Axles are all 30 spline so you aren't gaining anything there. The better cases are now getting expensive since all the car collectors have been wanting them for years, so that's working against you. The ring gear diameter is smaller than a 12 bolt (8.75 vs 8.875) but 8 3/4's are easy to setup (just like a 9" in that respect) Another issue is they stopped making these rears after 1974 so they aren't as plentiful to find.

9 inchers are cheaper and stronger, easier to find, and the aftermarket support is phenominal. That's why it's a popular choice.

Dana 60's or the 14 bolts are popular swaps among truck enthusiasts too, I won't get into the good and bad points of those but if you can find one cheap enough in working condition that will swap in without too much headache you might be money ahead.

[INSIDIOUS '86]

I have a plain 742 case sitting under the bench from an old race car. I just need a proper sized housing next. So I guess what i need to know is what size i need as i belive nobody can really extend housings can they?
Posted via Mobile Device

[Firebirdjones]

Axle tubes can be removed and new tubes installed. Requires a jig.

Cheaper and easier to to cut down a rear and weld new ends on,,,still requires a jig. Then you'll have to have axles made to length either way,,,,and it's starting to get pricey....

Finding exactly what you want may be tough. If you really really REALLY want to use a chrysler 8 3/4,,,,,,It's easier and less time consuming to call Moser/Strange/Currie (take your pic) and just have them make your bare housing to the desired width along with a pair of axles ready to go. In the end I'll bet it wouldn't cost much more money (if at all) by the time you figure in machine shop labor to cut a stock rear and then order a pair of axles anyway....

Just a thought..

[INSIDIOUS '86]

True. I just know that the 8-3/4 held up to the stroker 440 in the 67 gtx. All it had was welded axle tubes. The 742 case with 3:91 and strange axles to a spool.

Im building a 406 sbc to put in next and i just want a mechanical locker with 373 gears. I dont want the ten bolt to "maybe" hold up with slicks on the track. Because eventually a stronger turbo charged engine may find its way in there. And my philosophy is build it right the first time and if a 750hp dodge cant break a mild 8-3/4 then its good enough for me
I also want to be able to change pumkins at the track and its either a ford 9 or dodge and i would rather be dodge than the power robbing ford traitor haha
Posted via Mobile Device

[Firebirdjones]

That is the nice thing about the drop out 3rd members, Gear changes are a snap and take about an hour with a break in between

You can have your 1/4 mile gear in there for the weekend races, and swap it easily for that long road trip or cruise you want to take the following week.

[INSIDIOUS '86]

Originally Posted by Firebirdjones

That is the nice thing about the drop out 3rd members, Gear changes are a snap and take about an hour with a break in between

You can have your 1/4 mile gear in there for the weekend races, and swap it easily for that long road trip or cruise you want to take the following week.

Exactly. And with two tanks one can be pump gas and the other can be race fuel
Posted via Mobile Device

[smashingchuck]

you guys are being silly. Slap in a 12 bolt and be done.

[INSIDIOUS '86]

Originally Posted by smashingchuck

you guys are being silly. Slap in a 12 bolt and be done.

Cant change my gear ratio at the track. And thats what I want
Posted via Mobile Device

[WarBeard]

10 and 12 bolts strength difference is so small Not even worth it IMO.

[Firebirdjones]

Originally Posted by smashingchuck

you guys are being silly. Slap in a 12 bolt and be done.

Not at all, I actually exposed the 12 bolt truck weakness in my post above. the 8.5 10 bolt is a better piece once an axle upgrade is done,,,but you can't do a darn thing about the tiny pinion in the truck 12 bolt.

If you've ever had the pleasure of swapping gears in less than an hour by swapping pumpkins it might make more sense.

I do this with the 9" in my SCJ mustang. The factory 3.91's are nice around town but occasionally a long 4-5 hour trip is taken, and I just drop in another pumpkin setup with 2.75's and it becomes a 75 mph highway friendly cruiser.

It's not a new concept, there are various companies that even make a carrying case for your pumpkin so it stays clean and dry, easy to take with you