I have scanned through this thread, and I may have missed some things but here is what I would suggest.
Ditch the lift rule cam...it will kill a street car and you will end up spending more on drivetrain to compensate for the duration. (gears, converter etc)
Check out beehive (conical) valvesprings from crane, these will allow you to run alot of lift at the same installed height as the stock vortec springs. WITHOUT MACHINING.
If you are going to rebuild the bottom end, get a better piston than those 345's something with a flat top and two valve reliefs. There are some really reasonable forged pieces out there that are well worth the extra coin. You just need to know what you are looking for specifically because these are not always advertised widely in the popular shopping spots.
Get rid of the steel shim idea...GM makes a gasket (10105117) that is a composite and is only .021 compressed thickness. (they advertise it as .028 but I have checked them myself) This will eliminate the common problems with steel shim head gaskets and only give up .006 quench.
Like CNC said, you will not be happy with your "budget" motor unless you put a little extra cash into the places that count. And if it takes a few hundred bucks extra to be able to run whatever cam or compression ratio you want then you should go for it, otherwise you will probably be doing it later.