Why does a Chevy 350 cut out while accelerating but rev up and idle just fine?

Check your fuel pump/fuel filter. On the newer fuel injected cars/trucks a restricted fuel filter will allow the engine to perform properly until a fuel demand limitation is reached. Operation may be normal at 60mph and then feel like it has hit a wall at 65mph when the fuel delivery is not sufficient for engine operation at the increased load. Acceleration is the same condicition low fuel flow due to the blocked filter not allowing full fuel flow to the engine.