3.5l dohc 95 model idles but wont rev chokes and splutters engine recently rebuilt

Sounds like the timing is off or something wasn't synch'd up correctly during the rebuild. Check the timing and make sure the vacuum lines are connected correctly, especially the vacuum advance which advances your timing when the engine RPM's are increased. Start your timing at 5 degrees before top dead center, the 5 mark on your timing marks, this is the most common baseline setting for timing. If you have to set it advanced beyond 10 degree or retarded beyond 0 then your timing chain was not aligned correctly between the Pistons and the Valves or cam shaft.