Been thinking about supplementing or replacing the factory dash air with an under dash unit. The hole AC system works and is tight with no leaks but since it is a 74 most of the cold air leaks out inside the dash through those powdered foam seals that were on the factory, 2 dozen or so turns, ducting. I've found add on evaporators to go under the dash but most are at a minimum 11" deep. Has anyone found a fairly shallow unit, wider would be better to me. Also do most just tee and keep what's in the dash going or just cut it loose and just use the under dash unit? It is nice sometimes to use the air for clearing a fogged window. I've got the factory compressor about the size of foot long piece of light pole still sounds good and the system doesn't leak. So any ideals or links would be appreciated. ...