Besides boring up .060 safely you can mill the head quite a bit but I'd stop at as little as it takes to get it totally level.
As for the head I doubt there is any stock factory head that would not benefit form some good porting relief and polishing.
Get yourself a copy of the Chevrolet Inline Six-Cylinder Power Manual by Leo Santucci. It is written for the next and last generation of OHV GM inlines but there is much to learn from it regardless. The ignition change to electronic is crucial in my opinion. Helps starting immensly (spell check please) as well as overall performance. The Desktop Dyno (yeah,..I know) claims mine has 174 HP which I greatly doubt but it does run nicely and has power. These old girls will run a higher RPM than most of the folks here like to hear but back in the 50's we'd run the guts out of 216's and 235's with almost no internal damage. The price to fix one has become so expensive that most guys are now afraid to run them. I say let'r go. It's only iron so have the fun.
