The deluxe belt style was available in 1970 ONLY so the belts in the auction are correct for 1970 ONLY. The usually messed up parts book, section 23 says that the part numbers that the guy listing the auction are for V and L cars only, Valiants and Darts. The seller seems to know exactly what he is talking about so I would say the parts book is incorrect regarding that part number: 3453 603, which it also says is correct for 1971 only, again, another error.
