My rearend is about to go out so it is going to be the first thing i replace in the rebuild of my 89 GTA. I was wondering how much HP and torgue can the strange 12 bolt handle? Also on the strange website it says the rearend is only compatible with 93-2002 brakes so do i need to buy a complete brake set from an LT1 or is there anyway to use the stock brakes?

 

A typical 12 bolt can withstand 600 hp. There's no way to determine a maximum since there are too many variables.

http://members.aol.com/InjuneerZZ/Strange12.htm

Take the amount of torque your engine produces. Multiply by the first gear ratio. Multiply by the diff gear ratio. This gives total torque to the wheels and axles.

Engine makes 500 pounds of torque
Uses a 3.06 first gear'd 700R4
Has 3.73 gears in the diff
Makes 5707 pounds of torque

It's recommended that axles size be strong enough that one axle can withstand the total amount of torque

Normally a 12 bolt only has 30 spline axles but you can upgrade to 33 spline. Bigger isn't always better since there's a lot more weight in larger axles and if you don't have enough hp, then it's extra weight and money spent.

30 spline axles can take 6200 pounds of torque each
31 spline axles (Ford 9") can take 7000 pounds
33 spline can take 8200
35 spline can take 9600
40 spline can take 12,000

Because I use a 1.76 first gear powerglide, my car roughly produces 5500 pounds to the wheels and only uses 31 spline axles in a Ford 9". I have a long way to go before breaking one. These are all for aftermarket axles. Factory axles are much weaker.

 

Be careful when buying an aftermarket 12-bolt. A lot of them are set up for 4th gen cars and are too wide for a 3rd gen with stock wheels. Moser, Currie, or Strange can all make the axel the right width for a 3rd gen so you can reuse your stock wheels or aftermarket wheels with the stock offset. They can also make them to accept the factory brakes (though the factory brakes are kind of wimpy, but if you're on a budget I understand).

As stated, the how much power deal is a heavily loaded question. A 12-bolt should be adequate for all but the most brutal cars. I would definately go with a girdle cover and studs in the caps though. Even with stock 30-spline axels it should be up to the task, but the torque guide is really the best way to figure that out.

 

thanks 1 thing about the brakes is if i do go ahead and buy breaks off an lt1 then am i also going to need new rims or any other parts??

 

It depends on how wide the rear is. If it is 4th gen width you'd need new rims. If they can make the rear 3rd gen width you'll be fine with stock rims (or aftermarket rims with the same offset). The 4th gen rear is about 3" wider I believe, or 1.5" per side.

 

no im going to have the rear built to the 3rd gen width i just wasnt sure if the lt1 or ls1 brake setups will fit inside the stock GTA rim.

 

I don't think the brake size is an issue. The stokc GTA rims are 16" I believe, and I think the stock rear rotor size is only 11.5" or so. You should be good. You might want to try to post of the brake board just to be sure. I'm sure you'll find someone there who's runing the same setup and can say difinitively that this will work.

 

I have the Strange 12-bolt in my car. I went with 33 spline axels, upgraded posi and I ended up using crum brakes from a 96 Firebird 6-cylinder car.

When I ordered mine, they said the rear should be good down into the high 8's. It comes with a girdle type cover and Ford bearings for strength/elimination of c-clips.

Its a quality piece but it is going to cost ya about $2500 after all is said and done.

If you need any help/tips/pictures, let me know.

 

I went with the eaxact same thing - just using the PBR rear discs (Baer conversion from iron kit) - and it does run about $2,500.

 

the LT1 brakes clear no problem.

the LS1 brakes require ALOT of grinding.. enough that i wouldnt want to run them.

get the LT1 brakes..... its actually the same PBR caliper as the later 3rdgen rear brakes.....

 

Which setuyp do you get if you want to run 17X11 rear wheels and keep the wheels in the sweet spot (not sticking out, not hiding the diff cover)?

 

doesnt matter.

just get the wheels in the proper offset.













now to go 100% agienst everything everyone said in this thread so far:


get the 4thgen offset.
yes, your stock wheels stickout some... not past the fender, not enough that a "normal" person really notices, but alot of car guys might notice... everyone can notice if you point it out.


now, with the 4thgen rear, the 3rdgen wheels look a little odd... but ALL 4thgen rims fit...and vette rims.... including the aftermarket rims... so you have HUGE options for the future... why limit yourself?


on the flipside, you could always run bolton spacers on the 3rdgen axle..... if your track lets you get away with that.

 

That really isn't going 100% against what everyone else said.

The wheels stick out, just past the lips of the rear wheel wells. I've seen it, and it looks tacky. It's sort of like stinkbug stance. Better left in a bygoen era.

 

hey when i upgrade to the lt1 brakes in the rear are the brake lines going to be the same size as the stock rubber lines??