I got the test procedure from ChevyMgr, but most of it involves using something called a "J 43600 ACR 2000 Air Conditioning Service Center" to measure pressure values.
I think what we are looking for is this:

 

Thank you for your help I will check it today after work it's only 74 and low humdity today so I will refer to the chart. Thanks again

 

Today I had a new compressor installed in one of my "toy" cars, a 1988 Fiero GT. The temperature coming out of the vent was 40 degrees with the outside temerature around 80 today in sunny Florida.

I've had this car for 12 years and at least three compressors have already been put into the car. Rebuilt ones don't last. The last one was a used R12 compressor that was never really evacuated properly for the R134 refridgerant, but it lasted more than three years.

 

Yeah, by the looks of those numbers in the chart, mine is probably working to GM specs, sad as they are.
I wonder if the stock A/C could be modified for better performance, like changing to a larger evaporator or something?

 

prod....

are you sure you're reading the A/C charts correctly?? I mean, Toronto, how hot can it get there???

I live in Arizona, with summertime ambients hitting 115-120. And my A/C cools to perfection.

 

The weather is just getting nice, 20 deg C or so. The average summer day is in the 25-29 range. The chart says I can count on a difference of 5-6 deg with the A/C, so why even bother switching it on? Its not even enough to keep up with the heat coming up off the dash, Ive tried it.
Hopefully the difference will be more noticable once the real summer weather hits.