2003 silverado 1500 2wd 4.3L 5spd manual

i recently had the engine rebuilt past factory specs. Its bored .030 over, shaved deck, compression 10:1, lager cam .500 lift, heads ported/polished, balanced/blueprinted, billet aluminum distributor with factory gm internals (cam sensor, rotor, drive gear), factory coil, 8.5mm plug wires, factory spark plugs (.060 gap), cold air intake, magna flow exhaust, new gm crank position sensor and cam postion sensor.
after installing it in the truck and firing it up, its giving me dtc p0016. ckp/cmp correlation. i followed gm's procedure step by step for installing the distibutor. the engine starts right up and idles fine. but when i hook up my flashscan v2 and run the scan tool, the cam retard pid is showing 59 degrees at idle and when i rev the engine past 2000 rpm it shows 56degrees. the cam retard is suppossd to be at 0degrees (+/-5). im pretty much stumped as what to do.
im new to the scanning and tuning world but very mechanically inclined. any assistance is greatly appreciated. thank you