I wouldn't run the rods any tighter than .002 and the mains can go as big as .0025. Critical clearances are connecting rod side clearance, crank end play and oil pump gear to cover. You'll need at least .017 on the rod side clearance and the crank end play should be around .005-.008. The pump gear to cover should be no more than .0015-.002. Use the oil pump kits they make to increase the volume/pressure of the pump. Piston to wall should be whatever the piston manufacturer recommends. And make sure you measure the piston where they say to check it. Also... if you're not floating the pistons on the rods... make sure the guy checks and makes sure the pins are very free to move on the piston. This is generally where piston failure is 1st seen aside from fueling issues. Piston ring gap is crucial!!! Again... follow the recommendations from the ring manufacturer. You'll never go wrong with a little too much (if your file fitting your rings), but if you don't have enough ring butt clearance, the rings will butt and lift the pistons heads off eventually. Make sure you use a new cam button and spring. Same with the timing chain tensioner. Make sure you modify your oil filter by-pass valve also. Remove the valve, tap it for a pipe plug, and install the plug. This will make it so if any trash enters the oil pump, the filter will catch it rather than letting it get into the rest of the oiling system.
The biggest thing to blueprinting is making sure everything is round, without taper, egg or barrel shape. When using your micrometer, make sure all the journals are the exact same size, and check them 180 and 90 intervals to assure non ovaling of the journals. The best way to check your bearing clearances would be with a bore diameter micrometer.
