87 IROC rear width?

[bart007]

I have recently acquired a wrecked 87 Iroc w/the 350 TPI engine. The rear end appears to be a borg warner with a factory limited slip and with disk brakes. I have searched the threads and came to the conclusion that this rear should measure approx. 61" I have also concluded from my research a 70-72 Pontiac Tempest rear should measure 61" as well. I am thinking of doing a swap, both rears are coil sprung and I am wondering if these measurements are about right? If so, I see a fairly straight forward swap. Any ideas on this?
Thanks

[MrQuick]

Yes the 87 rear is 61". They are not the strongest rears but should be ok.

Straight forward swap? Not sure about that. The angles on the lower arms are different and spring mounts are a bit narrower. I'd be selling the IROC parts and buy yourself a nice 8.5 10 bolt out of a 72 Chevelle. The 87's disc brakes will bolt right up to the early rear end. Grab the front sway bar, master,booster and combo valve out of it too.

[Randy67]

Definitely not a straight forward swap. Since it came from a torque arm suspension, there are no upper mounts for the upper control arms. It is also weaker than the 8.2 10-bolts that came in the car. Unless you plan to adapt the torque arm to the car, I would also sell the rear end and look for a 12-bolt, which is probably easier to find than the 72 8.5 10-bolt. Just my $.02.

[G-RIDE]

I am going to fit a 89 GTA rear end into my 72 Bird.

I thinking of cleaning everything off the 89 rear end and welding new spring leaf perches to get it under my 72. I am mostly doing it for the rear disc brakes and the possi track.

Any coments on this...Is this somthing you would recomend.

I too found the entire car and bought it out of a salvage yard so I'm also planning to use the entire 89 drive train in my 72.

GTA wheels and all.

[MrQuick]

You can do it but if you are doing it mainly for the pozi and disks brakes then I say you can do better. Your year (72) has so many more options since that size/style rear ran till 81. Find an 8.5 10 bolt and add the brakes.

The 3rd generation rear ends are not very strong as Randy stated above and would eventually cost more money later down the road when it fails.

[G-RIDE]

Thanks' for the info..

That's why I love this site.

[Randy67]

The Bird leaf springs setup definitely gives you more choices. One note, the Borg Warner rear axle has a larger bolt pattern where the brakes bolt up to the axle ends, so their brakes don't fit the early rear axles. I got a set from a 88 Formula and found this out the hard way. It was the cast iron caliper setup so not a big loss.

[G-RIDE]

Thanks' again - I'll make a note of this when ever I upgrade the rear end.

I think I'll put the 89 GTA rear end for now and get this bird flying.

Anybody need some GTA body parts?