I have a 71 Corvette convertible, 350 motor with the factory AC system .  The systems works as it should when I put a temperature gauge at the vents the AC is cold but it only keeps the car comfortable not really cold . I have been look at the Classic Auto Air perfect fit system . Does anyone have any experience with it , does it put out more volume of air than the factory system. If it will keep my Vette cooler I am all in but don’t want to spend the money for no or very minor improvements. Thanks

I've seen writeups on using a C4 fan because it has a greater airflow capacity. It does require a spacer between the fan and the firewall because the fan itself is bigger. You might give that a shot as that would be considerably cheaper than replacing the system. 

If you decide to replace the system, you might check Vintage Air as they have a lot of good reports. 

Thanks I will look into the fan , one of the advantages for me with Classic Auto Air is they use to be in Tampa and do installs instead of strictly selling systems and the guy who did the installs who is retired would do the install for me at considerably less than a shop.

To me, in a C3, there is only one a/c setting.....Max.  That way you are recirculating cockpit air.

There is a modern, direct drop-in replacement for the old A6 compressor.  It's call an S6 (not a Sanden).  Don't know if that would cool any better though.  Paint it black and it darn near looks factory.

Sounds like you need to insulate the interior better to block out outside hot air.

Just a consideration, the under dash box that holds the small radiator for cooling is probably not up to capacity. Many things get into it from outside. Leaves, dust, animal gatherings, loose sealing foam, or the core itself is not free to flow. I'm guessing the heater does not work as it should, if it's used at all. How about the space between the Main radiator and the condenser for the air conditioning. Also the duct work may not be connected very well, as the years and bumps take a toll on the foam and connections. 

Just reread the beginning. A Convertible is FULL of leaks. Can't keep the cool air inside. Fighting a loosing battle. I have a 72' drop top. The hard top keeps cool air inside much better, which I have also. Put a tunnel baffle on the bell housing. It keeps the heat from radiating up in the car. 

Thanks for all the advice , I just did a complete redo on the interior. I gutted the entire interior and put heat/ sound insulation everywhere . I removed and cleaned all the duct work , it was filthy. I had an AC shop check out the system and they said it was getting as cold as it should and blowing fine. Don’t get me wrong it will keep the car comfortable in 95* Florida weather , but nothing like a newer vehicle. We were out last Saturday in the heat of the day , my top is white and lined , you could touch the top and it was not hot , the heat felt like it was coming through the side windows and windshield ( may tint them ?)  It is just I would like it colder and of course Classic Auto Air and Vintage Air both when I called them said their systems would accomplish that. But what would you expect them to say. I hate to spent the money and see no significant improvement, however if it will give me a noticeable improvement that’s another thing.

I installed a Vintage Air system in my '75.  One thing about their system is that it blocks off all the outside air ducts so there is no chance of air entering the cabin (assuming the rest of the car is tight).  I'm a bit tall so I always ride with the driver's side T-top off so I couldn't tell you how well it can cool, but it does blow cold air around my feet which helps.

Of course, I'm in Virginia not Southern Florida. . .

One thing I did notice is that the heater works much better than what I had as stock.  I had thought there was some blockage in the heater core of the old system, but it was all free.  I think maybe there was a lot of outside cold air intrusion through the heater.

I found installing the Vintage Air system was a large project, but their directions and support were very good.

If it were me and the stock system was cooling as well as you say, I don't think I'd go to the trouble of changing it.  Some comments were made about using a more modern compressor or other parts which may be all that is needed.  The newer systems use R134A refrigerant rather than the older Freon R12 so there may be some issues with compatibility there.

One thing to remember that while you can charge the old factory system with R134a, it will not cool nearly as well as it did before with R12.  I say that realizing that R12 is very expensive these days.  

One thing that I learned while installing factory A/C in my '73 that I ordered without A/C was that the compressor used in the Corvette had less displacement than the compressors in the big cars. I'm not sure if a larger displacement compressor would cool any better. The evaporator didn't appear to be much smaller than a bigger car evaporator though. Not sure why the Corvette got the different compressor. 

tj316: what's your center duct temperature at highway speeds with the A/C set on MAX?