The body on the New Yorker is the same as the smaller series. The New Yorkers extra 4 inches is all ahead of the firewall.
This started in 1957 with DeSoto and Chrysler models sharing the same bodies. The Firesweep and Windsor sedans and wagons had different doors, but the bodies were the same as their bigger brothers. (No, the 1957-59 Firesweep and Windsor did not use the Dodge body.) The difference, again, was all ahead of the firewall. 1962 was the last year the New Yorker was a Newport with a 4 inch longer hood.