Earl here,
just purchased 77 Landau with 466 original miles. Factory AC. Factory heater core leaking, brass.
Any suggestions for best place to purchase replacement?
thanks in advance.

 

Rockauto has a listing for a Spectra Premium with brass tanks and the rest copper that looks nice but I don't know anything about that brand. Napa Auto Parts? Check with a radiator shop, they should know the best replacement units, or maybe repair your factory piece.

 

I Sounds like a great car , I also would keep with a brass/ copper heater core.