I have a 71 Corvette and I have replaced my A6 compressor 3 times due to the front seal leaking oil, not just seeping. These units are 4 seasons rebuilt units. Anyone have any suggestions on where I can get a dependable compressor that won't leak a lot of oil ? I know they all are designed to seep a little bit oil. When I get the rebuilt unit I drain the oil ( 3 oz's ) in the compressor and then I add 3 oz's to the compressor and 3 oz's to the system. Any help would be appreciated.

That is rather odd. I would just have to guess the rebuilds were not done correctly. The front seal in not hard to do when you have the special tools, but it is VERY touchy.
Perhaps a compressor from a different source?