i just checked my 68 firebird parts car an it has a nod iron rearend in it . since it has that does it mean its a posi ? the car had a 4 speed in it an i do think it was factory . i think the car also had a 4oo as it has a lot of thing that a 400 car would have ?
5150 4cars = carzy4cars my car= 68 firebird 350 jim butlers ported heads an intake , 4 speed , 3:73s