[Alan Roehrich]

I would not advance the cam 6 degrees.

Were I you, I'd consider a mild camshaft and a really good timing set instead, with a new set of valve springs and seals. I've had really good luck with some of the budget cams that Speed Pro sells, as well as one of the small Melling cams. I buy them in kits, with lifters, they are pretty inexpensive. I usually put something simillar to the old stock Z-28 spring on them, they're inexpensive, too. A really good timing set will prevent the near instant slack you get with the cheap ones, and the stock ones, because the sprockets are not heat treated. You can often do the whole job for under $250, and you probably have it apart far enough to do it all easily.

A real good tune, as suggested above, will do a lot.