Hard start after replacing distibutor & battery

Silverado 1500 yr=2002, 4.3L, V6 vortec.

This is my wits end.
here is what has transpired.

recently replaced distributor, finally got timing right (via manual cranking of crankshaft etc while in nuetral and batt disconn.) Now it fires correctly but wont start, does fuel pressure (regulator, ecm, etc, ) become "disabled" when battery is completely discharged or disconnected? As I have spark at coil and at plugs. Does system need a "prime" i.E. A bit of gas in the T.B. Opening to get fuel re-applied? I have not tried this yet, as I would like to hear any input from someone. This is a relatives' truck and am doing him a favor by replacing the distributor (original was almost destroyed, upper bearing in housing was gone), getting timing right was difficult but I did get it as the engine turns over normally, his battery was also near dead so I replaced that, hence the? About discharge/disconnect with respect to the fuel pressure situation. NO, I do not smell leaking gas anywhere so I do not suspect fuel pressure regulator. Any help would be great.