I just recently installed a 97 trans am motor in a 94 z28 i picked up. im keeping it obd1 so everythings been swapped over. Well since the 97 trans am manifolds are different my buddy had a good set from his 95 z28 camaro. So i installed them, and im trying to figure out where the drivers side o2 sensor is suppose to be? only the pass side has the o2 in the manifold...so will i need to drill a hole in the ypipe for the 2nd sensor? the exhaust is the stock exhaust that was in the car origianlly.