1968 Barracuda 318 Smoking....good compression

This may sound strange to ask, but do the valvecovers have any leaks?
We had a 70 Coronet that smoked pretty bad after it was running for a min or so and then after about 5 min it would clear up.
It would smoke out the entire block and after 5 min of running it didn't smoke at all till the next time it was started.
The valve covers leaked and the oil was seeping into the exhaust gaskets and burning in the manifolds.
Once the Valve cover gaskets were changed it stopped completely.

I got it for $300 bucks because of it, and knew why it was doing it. :-)