I've been converting my '88 740 to R-134, and one thing that has surprised me has been that there is NO "High Side" port present to measure compressor discharge pressure on the vehicle.

In addition, the ONLY port is an odd looking QD connection that formerly came off the connection piping between the Accumulator and the Evaporator (see photo below) via an odd set of pipes. I no longer have it to photograph (I threw it out after brazing the piping closed. I did this to reduce the number of threaded/O-Ringed connections to leak).

It's not like anything I remember when filling with R-12 years ago. It's long and the size of my pinkie finger!

For the Low Side/Fill Port, I used an R-134a low pressure QD adapter that I threaded onto a Schrader valve on the Accumulator itself for the Low Side. This is the one opposite from the one onto which the compressor switch threads.

For the High Side port, the R-134a High Side adapter I purchased had no place it would thread onto, so I re-tapped it larger to thread onto the high pressure Schraeder valve right at the compressor body itself (it is a much larger diameter Schrader valve than on the Accumulator).

BOTH adapters were equipped with O-Rings that seat against the tip of the Schrader valves, and I used Nylock Blue on the threads as well.

The High Side adapter is really inconvenient to get to (behind the compressor, below the alternator), but I was told that when using a VOV (Variable Venturi) the High Side pressure readings are erratic and fairly useless due to the variable opening afforded by the VOV.

Just curious if anyone else has "conventional" A/C ports on their cars, and how they charge their systems w/ R-134 refirigerant.