Well, first thing to do is decide on a power level and go from there. If you are making in the 500 hp or less range, I would go with hypereutectic pistons. ( tight clearances, quiet, less emissions when cold, more heat stays in the combustion chamber ) Over that, I would select a forged piston.
The stock cylinder heads are ok, but not great... they are basically boat anchors in today's world. A set of Edelbrock Performer RPM heads would definitely a step in the right direction, as well as other heads from different manufactuers.
If you buy complete heads, check to make sure the installed springs are going to be good enough for your camshaft, otherwise you will waste money going that route. Regarding cams, I would select a retro fit hydraulic roller if you intend to keep the RPM down below 6000, and even that is the outside unless you have a 'rev kit' to keep the roller lifters from leaving the nose of the cam.
Solid rollers can make more power at higher RPM, but the caveat is higher spring pressures, and driven on the street require maintenance in the form of valve adjustments. Even with relatively low duration compared to a flat tappet camshaft, a roller will give you MUCH better cylinder filling and scavenging. It's worth the money to retrofit.
You could use the stock crank if it's in decent shape... even a cast crank will survive a 550 ~ 600 HP power level. However, if it needs turning, and the rods need resizing and you need to buy pistons anyways.... it would make sense to get a complete balanced rotating assembly to drop in your block. Displacement is king!
