Currently have my engine and transmission out and plan on replacing the evaporator core and heater core. Is there any advantage to doing this now or is it pretty much the same pain to do after the car is back up and running? I got this car in 1982 and it has mostly sat in my garage since 1988. Its a numbers matching 289 2V auto with factory air, power steering, etc. My goal is to get it back to where it was after I got it home from the paint booth in 1983. A nice weekend driver. Any input is greatly appreciated.