I have two cars I am consolidating into one.

I have an LS1 rear end 10 bolt. and one 87 GTA 9 bolt.

Which one should I use and why?

 

 

I did, didn't find the input I was looking for.

 

well aftermarket support for a 9bolt is slim, while the 10 bolt is plentiful, the 4gen ten bolt as you may know has a wider track width so wheels may become a concern, and the 9bolt is a "direct " replacment of the axle you have already, well the 4th gen is too but its overal 3 inches wider i belive so. theres your options.
9 bolts you will get mixed emotions over how much power they can take etc. but its in preferance, i say the 4gen rear just because there is more of an aftermarket for it, and you can run the fancy 4 gen wheels too.....

Luke

 

I would go with the 9 bolt as it's made for our 3rd gens. I just rebuilt mine and it was very easy and only cost me about $300.

The 4th gen sticks out a couple inchs.

You might even want to try and sell them both and locate a 3rd gen 10 bolt. Stuff some 28 splines and a zexel in it.

 

Depends on the wheels you are using if you use the 4th gen wheels the ls1 10 bolt will be the best option. If you use the stock third gen wheel use the 9 bolt. The 2 inches on each side looks retarded if you ask me.

 

Really? I really get tired of people spouting off with negative comments, when they really have NO CLUE as to FACTS & are just assuming the extra 2" will cause a problem.

It gets old posting this pic, to show people they don't know what they are talking about....This car (with a 4th gen rear axle & stock wheels) looks retarded? I'd say it's a perfect fit.

 

I also was in the same boat. Whether to spend $300 on a rebuild, or to buy a used 4th gen 10 bolt. I ended up rebuilding mine. Glad I did. I Packed in the shims tight so now they act almost like a locker. It is a very easy set up also.

Do either of them have disk brakes? If so I would take that. Is the 9 bolt a 2 or 3 series carrier?

 

I would go with the LS1 rear. Better LSD, much better brakes and better aftermarket support. Only thing that is kind of a pain in the butt is making e brake cables work, but that is doable in an afternoon if your patient

 

what would be better between an LT1 rear and an LS1 rear? i noticed Hawk's has both available for the same price and was wondering what the differences are

 

LS1 rears are the better of the 2, better LSD and larger brakes with an internal drum style e brake making them much easier to deal with.

 

did you do the rebuild on the 9 bolt yourself? where did you get the parts?

 

I didn't need any parts. All I needed to do was to machine and shim the cones. You can get parts from 9bolt.com though.

 

when i was swapping drive train. i had three 4thgen rear ends laying around and one 9 bolt all being 3 series. Two of the 4thgen rear ends i swapped out of friends lt1/ls1 cars do to rear end failure. I knew the facts of both the 4thgen and 3rdgen rear ends. i ended up going with the 9-bolt.
i maybe going with a after market one later on but if i don't im still going to do 13" rotors and 2 or 4 piston calipers if i keep the 9 bolt the only thing i might get hung up on is the e-brake cables with the new brake setup

 

My posi and ring/pinion are trashed. One took out the other. Just going to build the ten bolt. Not paying 350+110 for shipping for just a posi rebuild kit.

 

I got a 4th gen rear to put in my car, its got posi, disc brakes, and 3.42 gears, which will be a big improvement from what i have now. but eventually i will put a moser 12 bolt in there to hold up to the power of a 383. btw I'm going to be running the stock Z28 rims on the 4thgen rear, so they will stick out a little bit.

 

The stock 3rd gen wheels will NOT stick out any,past the top of the fender lip. Virtually FLUSH, but not out any.

 

yeah i was just meaning they will stick out farther then they are now. But i think that will make it look cooler

 

My car came stock with a 10 bolt 2.73 with drums. Then I swapped in a 9 bolt 3.27 with disks. Now I'm looking for a 10 bolt 3.42 with LS1 brakes.

I only want to get rid of the 9 bolt for the 4th gen rear because I am afraid of the repair cost of the 9 if it ever breaks, and because of the larger brakes, better gear ratio, and cheaper repairs of the 10. If only I can find one nearby that is for sale.