Just finished servicing the new A/C on the 78. Bought the car a couple years ago and the AC was my last big refurb. Only thing left on car from the old A/c system was the Evap and Condenser. Wiring ,hoses, compressor and brackets all missing. I kept the old evap, took it out, cleaned and vacuum checked it. Installed Sanden style compressor, lateral condenser,hoses etc. Finally got up to 78 degrees here in Indiana so I took it out for a check ride. On open road, with AC thermometer in vent, I was getting about 50 degrees. Not really impressed with that. I then realized I neglected to close my heater hose shutoff valve I installed so I closed it. That dropped the temp in the AC vent to approx 37 degrees. It should hold 30-36 ounces of R-134 but I put in 4, 12 ounce cans. Low pressure got up to around 35 and high side about 175. I do bleed R-134 out of the low side servicing hose each time I switch cans to get the air out.  So I figure I got around 40 ounces in the system. At idle, AC temp  would climb to about 45, but I can live with that. The original fan puts out good volume of air through the dash vents. I did block off drivers side floor duct to put more air over to the Mrs. side. Gotta keep her happy!