Trying to get my heater core for my 60 Buick replaced/repaired. It's pretty bad, so it's probably going to have to be replaced. I'm tired of freezing my butt, toes, legs, fingers, you-name-it off during the winter months. And not having a defroster SUCKS!! Don't know if the old hollanders will interchange heater cores, but could any of you with the appropriate year book look up which year(s) of GM will interchange? I'm thinking 59-60 Buick, Cad, Olds, and Poncho. Chebbys any different? BTW, the heater core has the heater control valve bolted to it, if that changes anything.