i have a 9" rear from a 70 ford truck, 3.03 posi, it's currently installed in my 69 mustang, what would it take to put this in my 98 z? also as far as gear swaps go, what would it take to put 3.93 in it(im not talking in depth, just basic, i heard that if you go higher than 3.27 you have to change the posi unit)?

thanks
josh

 

It would take some serious fabrication for a torque arm mount. AKA just buy one made for the camaro already.

https://ls1tech.com/forums/showpost....3&postcount=37

 

ok, but as far as the basic 9", it would work, other than the torque arm? just trying to increase my knowledge of the car part world

 

You can take the centersection out and get some better gears put on it. I'm almost 99% sure you don't have to change posi's for different gears. I've never heard of that until now. Then i'd suggest you just buy a Moser housing and axle package. It'll run you about $900 bucks then bolt in your posi center section and go. Some people say the stock center section case isn't very good but i've seen a guy run 8's at 160+mph on one. He ran it like that for years until he turned up his Nitrous at the line and broke it. Then he upgraded to the Ford cast iron "N" case.

Edit: what kind of 69 stang do you have? fastback? Mach 1? why would you take the rear end out of it? I've got a 69 Mach 1 428cj.

 

its a mach 1, 351 w, the mustang is m baby, the z is my beater, i was thinking or getting a new 9" for the stang, then putting the old one in the z. thats a good idea about the moser housing.

 

I got to thinking are you sure its a truck posi? Truck differentials are usually 31 spline, your mustang should be a 28 spline axle setup. Only big blocks and Bosses got 31 spline setups in the mustangs. So unless someones changed the axles that posi is a 28 spline. Which means you'd have to sell it to get you a 31 spline posi to work with the new Moser axles. Do you know how to tell what if you have a 31 spline axle with out pulling it? Maybe someone replaced them at some point.

 

hmmm, interesting, all i know is that i bought a whole 9" from a guy that said it had come from a truck. i took out that center section and put it in mine. if it's posi when you spin one tire, the other spins the other way right?? i doubt that it has 31 spline axles, but it is possible i suppose.

 

would a 9.75" rear from a 2002 lightning fit?

 

That wouls most likely be an open rear(non-posi).

 

yes spinning the opposite way means non posi.