I'll be pulling out my engine this summer and rebuilding it. I'll be installing vortec heads and intake, new cam, new pistons and rings, roller rockers, and a new timing chain. The engine runs fairly decent now but I figure I'd just rebuild the whole thing while I have it out (I want to repaint the compartment anyway). She smokes a little on start-up but thats it. So do you recommend that I have the cylinders bored out while I have the block apart? Or would I still be leak free going with standard bore pistons and new rings. Also, about how much do machine shops generally charge for cylinder boring? Thanks.