2 "Ton" A/C in 70 AMX

Top picture is an original paint 70 AMX I bought, fixed up and sold years ago. Middle picture shows the A/C vents the original owner installed in the rear carpeted panel and in the kick panel under the 1/4 window, the passenger side has the same set-up mirror image to the drivers side. The bottom picture is the 2 "ton" rated capacity A/C unit taken from a limousine and installed in the trunk of this 70 AMX, with a drain pan under the unit with a drain line out of the bottom of the trunk, with Freon lines run under the AMX to the engine compartment and hooked up to a non-AMC type of compressor with homemade brackets The original owner stated that this unit ran so cold, that it would spit ice crystals out of these (4) vents. Prior to this custom A/C installation, the owner had converted this AMX to run on propane and had the propane tanks in the trunk with lines run to the engine compartment. After I removed all the A/C equipment, it took me the best part of a day to cut round patches and weld up all of these holes from these (2) modifications. 

Talk about freezing your bum off! Ha!

Yep factory, or most modern full sized car and truck setups are well enough for cooling. Though when swapping out with modern condensers, be sure to keep up with sizes relative to cooling capacity. Most R134, have larger condenser surface area than R12 counterparts. The closest replacement size for my system's cooling capacity is a bit larger than factory. I think Farna used a Dodge Stratus condenser, which is bigger than factory for his a/c setup.

The AC system is also based on the airflow and standard operating temp based on a drop. You still have the same CFM from the blower and plenum so the volume of air isn't changing. When you start hitting 35 to 37 degrees at the vent it's colder at the evaporator and will ice over reducing flow.

The big weakness in these first generation AMX and Javelin systems was airflow distribution not cooling capacity. The two center vents were simply not enough to cool the interior evenly. The same is true of the 67, 68 and to a slightly lesser degree the 1969 big car systems. Blower volume was also barely adequate. The second generation AMX & Javelin systems doubled the number of dash vents which was a big improvement.
The first generation systems with those lame rubber "floor cooling" tubes on the evaporator housing are a joke. It's best to either cap them off or remove them and use hole plugs in the openings. They bleed off valuable cool air to the floor when the upper outlets need all the cool air they can get.