I'm guessing here, but I think if everything is working
correctly the a/c should work as good as any car.
The fact that it is a 79' does not make it inferior
as far as its capability to cool.
I had my 82' diagnosed with a bad compressor
and the shop only put enough freon in it to try
to get the compressor to work. (3/4 lb) I was
on my way after a $45 dianostic charge and another
$40 for freon thinking I need a new compressor.
The A/C did work after that, not super cold but
noticable. They said they put a dye in the system
to detect where it was leaking, since freon will
work forever unless it leaks out (their words).
They said that the compressor may have started
working since the added charge of freon, and
that I never noticed the dye because an ultra-
violet light is necessary to see it. So although
I may have a leak, a full charge of freon may
have taken care of everything, though it may
have not lasted if I had a leak. So what I would
do is a search about how to be liscensed to buy
freon and try to charge it yourself. From what
I've read it costs about $20 to get liscensed
and then you can buy freon cheap enough to
make up for the $20.
I hope you got a deal on the 79', my 82' just
sold for $1,000 and the buyer was extremely
pleased. You inquired about it in July but never
responded to my email. I thought mabee you
were too flooded out in fort wayne to get to Mi.