I originally built my truck to look original so i kept the round recirculating heater because the heater box and gmc tag was mint with factory paint. I did put the new upgraded heater core in it from brassworks and it works great especially running at 199 degrees or hotter. I ended up wanting AC later and I figured I already invested in that nice heatercore so i was keeping it and that vintage air underdash setup looked period correct for the 50’s and into the 60’s so I used that and because it fit so well. Im very VERY happy with my setup. It blows 42 degrees all summer and it was a fairly easy setup and CHEAP for me to build.
