Vintage Air System not too cool????!!!!

I didn't realize you were using a different compressor. It MIGHT be possible it is outside the box for this system. A TXV is the only control device (as opposed to orifice/ cap tube) that is somewhat forgiving, but if a compressor is wayyyy too large or too small, the system will never be right.

These are designed to be "in balance." A large compressor will build high head and low suction too quickly, and if protected with controls, will short cycle. A small compressor will mostly just not cool well, if the TXV is sized such as to control the situation.

I'm a BIG believer in checking by superheat at the compressor. This insures that A you have enough cooling "coming back" to the compressor, and B that you are not in danger of slugging the thing with liquid.

Vehicles are especially troubling because of the vast operating variables -- not only the condenser conditions -- lack of airflow/ fan at low speeds, but the "box" (interior) suffers from vast extremes.