it's definately time for a rear and i could use some helpful suggestions. right now i'm running my stock 10 bolt with a 3.23 posi that does not want to work well with my new engine setup.

i'm trying to figure out something that will handle alot of power without robbing to much power if that's even possible. i've read all the stories on the 9" but i don't want to drain that much power as i don't race the car enough and i know they are pretty heavy.

is a well built 12 bolt strong enough to hold 500+ horses or should i look into a dana setup like 40's or 60?

i have a good connection with 12 bolts so i can do it for alot less money then the other alternatives, but i also know you get what you pay for so i don't want to build up a 12 bolt if i should have started with something else all along.

i don't race the car at the track very much, but i would like to know that if i want to play a little bit the rear can handle it. any personal experiences with this delema?

 

A Strange or Moser 12-bolt will easilly handle 800HP/800ft-lb or more. I saw one last to 950HP in a 3,900# convertible, running 9's. He only replaced it because he dumped in another 200HP and thought the 9-inch offered more strength once he went over 1,000HP.

 

The difference between a 9" and a 12 bolt is about 10 hp. You don't need a Dana. It's big and heavy and you're not producing enough torque that you need one.

Run what you have until it breaks, then buy a new diff. The 10 bolt is stronger than most people give it credit for.

I ran a beefed up 10 bolt into the low 11's with slicks and had no problems. I only switched to a 9" when I installed a transbrake.

 

well when i go to accelerate more times then not the rear feels as if it has a certain "slop" to it. as if you were to turn the drive shaft and after half a rotation it would grip. the u-joints should be good since they have less the 10,000 miles and the trans is new.

i can't accelerate even slightly hard without hearing a loud noise out of the rear and there is this constant wine as well that gets louder the faster and harder i go.

 

12-bolt is strong enough for two seasons in my 4,000+lb car with >700rwhp, >800ft.lbs, and an M6. Now, we'll see if it's up to an additional 100ft.lbs and an auto with a brake.

Rich Krause

 

Sounds like the thing is just worn out. There are after-market differentials, carriers, axel's etc. for the 'small' 10 bolts that are a lot stronger than the factory parts. Have your's rebuilt using some of these parts along with a new gear set with a better ratio. It will be plenty strong for what you want to do with it and a LOT cheaper than a 9" or 12 bolt - and you won't even have to take the rear end out of the car JMO

 

that's what i would prefer to do however i've been told by everyone in my area that it's a waste of money. that eventually, meaning very soon i'd have to rebuild it again...

 

My stock rear end with 4.10's (no heavy duty parts at all) and ~420 flywheel HP pushing it lasted well over 600+ runs down the 1/4 mile, not to mention all the abuse it got on the street, and it saw plenty of that too. What finally broke was the ring gear - took 4 teeth out of it when I left the starting line one day I can only assume that one rebuilt with heavy duty parts would last even longer.

 

which sounds about right...i've been told that anything up to 400 area will hold. with everything working well i should have well over that at the wheel so i need something a little stronger.

what would the average price to overhaul a 10 bolt be? say if everything in the rear was bad just to get a ball park figure.

 

With all new stuff?? It would be with a few bucks of a base 12 bolt
Posi $3-400
Axles $300??
Gears $200
Bearing kit $175
Install $2-400

 

see i could do a 12 for the same area why not do that even if i had to spend an extra $100 or so.....?

if it's definately stronger then a 10 bolt wouldn't it make sense?

 

Sure, a 12 bolt is definately stronger. But I don't agree with the prices:

You can get a stronger differential for less than 400.
Axel's, I would say use the stock ones. I think they could handle it unless you're doing a lot of hard hole shots with a stick car and sticky tires.
Gears - 175 for GM's.
Bearing kit - don't know, so I'll go with the 175.
Install - 200-250. If you pay more than that you're getting ripped off, IMO.

That's ~$1000. Add 15% on for incidentals and misc. I don't think you'll find anything in the 12 bolt department for $1150. Even if you use the numbers "AL" posted, that's still only $1475, so you're still at least $500 away from a decent 12 bolt - probably more.

 

If you do the above, it will be no stronger than the original. I think the original post was about a stronger rear end?

Rich Krause

 

i can get a 12 bolt setup that needs a few internals for roughly 2-300.....

granted new to new i know the 12 is more but if one can come across a 12 for a reasonable price wouldn't it make more sense?