I have a 1987 camaro 305 TPI that looses antifreeze. There are no external leakes. The exhaust steams sometimes.

a little steam in the exhaust is normal, a white cloud (when the weather and the engine are warm) is not.

does it suck the overflow dry?

is the oil milky and/or way overfull?

With the engine cold, take off the rad cap. fire it and let it idle till warm. rev the engine and look in the rad. if she blows bubbles, you gotta bad head gasket or a crack.

Jim, it does suck the over flow dry every two days. The oil is not milky or over full. I am going to have the oil sampled to see if it shows positive antifreeze. Thanks

Ed, I know you said no external leaks, but look real close at the corners of the intake manifold, and check for stains and trails of coolant..
It's very common, especially at the front corners.

It would be a good idea to pressure test the system.

You could also pull your spark plugs to see if one is alot cleaner than the others. Coolant could leak into the combustion chamber and not into oil pan. Just a thought.