I wouldn't put a new crank/pistons in a block without taking it to a machine shop, and this will take you out of your budget quick.
I would go with a cheap 2 bolt 350 short block and leave the stock crank/pistons in it. Get vortec heads or port heads to flow similar, go with an LT1 or LT4 cam, keep the TPI, and get a cheap tune. You'll have a reliable 300 HP for less than $1000
http://www.tbichips.com/bluewhale.htm
I came across this build which is very simple. I was pretty impressed with it, especially since it's a TBI truck