Originally Posted by 9T8W66
For the record 4th Gen Vin's don't distinguish between Formula and Trans Am. W66 (Formula) and Y82 (Trans Am) RPO's are the only sure fire way to identify the model.
That's not what he said. He said he has a Formula, as opposed to a V6, which can be deciphered from the VIN by the engine code.
You can use any 93-97 LT1 rear end with no modifications. They all came with disc brakes and a posi (like said above).
You can also use a 98-02 LS1 rear, but you'll have to swap to the LS1 style e-brake cable. Since yours is already cut, that might be a better option for you (LS1's have a better e-brake setup, and bigger rear brakes).