SNORX302

When the time comes (actually the money), i wanna rebuild my motor. I took apart a chevy 350 with a friend over the winter and basically can take apart and put back together a motor. i was wondering if anyone could give me a rough estimate on a couple of things
1)Anyone know roughly how much a shop would charge to do the machining on the block?
2)I'm looking to make around 300 whp-nothing crazy-Using the stock heads-could i port and polish them with bigger valves to get close to this number with all other usual bolt ons or
3)would i be better to just gasket match the heads to the gaskets for a nice increase?
Any help on which would be better would be great and if anyones got an idea to how much the head work would run too would be good
Thanks