I have the heater box out of a 96 Dakota that will be going into a 49 Dodge pickup.

I want to replace the evaporator and the heater core before it goes under the dash. I'm pretty surprised by the range of prices for the evaporators that are available. I have very little experience with AC stuff. Is there a price range, or a brand that is really good, or really bad that i will want to stay away from? Gene