A/C not running Cold

You could try a simple experiment: disconnect the heater hoses at the engine and run a loop between the connection. I had a prob with the AC in my '70 Cougar and the problem was the water flow valve on the heater hose was rusted through, so hot water was going to the heater core. OTOH, on my kids' '65 the heater core is always hot, so a '65 could not have that problem. I don't know if a '67 has the valve or not, but if it does that could be the problem.

Check this site... www.icorinternational.com/hotshot_opening.html#
then click on "mobile information"
It is possible that your Condensor and or evaporator are not large enough to cool the car with 134 as the refrigerant. But in AZ. the temps. this time of year are way up there. Ford, Chevy and Dodge had cooling problems in the early 90's when they switched from R-12 to R-134 (when ambient temps went above 100 F.) they corrected this by increasing the capacity of the a/c systems in the vehicles. This of course assumes that your condensor coil fins are not hammered and that your evaporator coil fins are not plugged up with fuss.
Also make sure that the components you have purchased are compatable size wise, everthing needs to be real close as far as capacity goes... +- 5%BTU rating (whitch is the amount of heat they can move). Make sure the compressor has synthetic oil in it cause mineral oil and alcybenzene oil IS NOT compatible with R-134. That being said, eliminate the heater core from the circuit by bypassing the heater core hoses as stated by "180 out" and see if that cures your problem.
If not find a shop that will order a couple 1lb. cans of Hotshot and have them charge your system with it and you will be chillin in no time. Hope this helps.