I was wondering how easy it was to swap n a 12 bolt rear end to an 87 iroc

 

Since there are no existing stock ones that fit these cars, the only way is to buy an aftermarket one... Moser, KTRE, maybe Strange... it needs to have the torque arm mount made onto the center section

 

If you buy a aftermarket one like moser...it is a pretty straight forward swap.

 

well i have a 12 bolt rear end allready just wanted to know if i could put it in or if it need to be from a certain car

 

Because of the torque arm suspension of the third gen, the only factory diff that fill be a direct bolt-in is out of another third gen. There was never a factory 12 bolt for a third gen.

If you plan on changing the rear suspension to eliminate the torque arm you'll need a 12 bolt diff close to the width of the third gen diff. The only 12 bolt that comes close is out of a first gen.

Don't use a truck 12 bolt. Internally it's not the same as the car 12 bolt and it's too wide for a car.

Trying to fabricate a way to mount the torque arm onto a factory diff isn't easy. You need to find some way to make a mount strong enough to take the torque and it needs to be attached to a cast iron housing.