I don't know if this will help and I am no older vehicle guru, but I have a Chiltons published in 1972 in front of me. They list 64-65 as 3.0 hours. 66-72 W/AC 4.0. If you want you can always add on these operations.. Boil and repair + 1.2 Repair core +.9 Reco... Login to read more.