On a 69 Camaro w/ factory A/C, are the heater core tubes location on the firewall the same for any engine, I saw a 69 for sale that is a factory A/C car, the A/C box and all equipment are gone, the seller says it is a B.B. car because of the heater tube location moved toward the fender, but I cannot find any proof this car was an original Big Block car.