For a 1970 Cutlass Supreme with AC and bench seat, can anyone tell me the appropriate duct sizes? I reference the bench seat as I believe there are different setups for console cars (please correct me if incorrect). My dash was taken out in the past and ducts were never put back as there is nothing connected to the back of the RH and LH vents and the center diffuser and defrost areas are a mystery. Looks like all the plastic is there but the cloth ducts are long gone. OPGI has various sizes ranging from 1 1/2 inches up to 4 inches and I was hoping to snag some before I tear it open.

 

The only difference between console & no console is the small plastic piece attached to the heater box right at the front center of the transmission hump. Other than that all the ductwork, weather fabric or plastic is the same unless your car came with an 8 track player. Then the lap cooler(long thin piece attached to lower dash) was 2 short pieces instead of 1 long piece.

 

To my knowledge, bench and console cars have the same ducting and components. A good source is http://thepartguy.com/ac-ducts_a_cutlass.htm. His site has a vey good illustration of the the entire setup.