Same engine/tranny config. as previous message about shift speeds (I-6, 4 spd. auto). Engine stalls-out if I hit the accelerator too hard from a stop. Accelerates OK if I tap the accelerator pedal a few times, then press the pedal normally. Worse when cold but present during all temp. ranges, and no diffs. when in Park or in gear. Choke clearance OK, accel. pump OK (unsure of nozzle angle), fuel/air mix OK. No hesitation at speed.

Sounds like float level/ accel pump problem. If the float level is too low then the accel pump can't deliver enough gas. The accel pump delivery can be adjusted as well as the the float level. Is the warm-up tube connected to the exhaust? How about the ignition system dwell?

I just replaced the accelerator pumps on my '71 250/8 and it cleared up a similar problem. Does the car idle smoothly while stopped and in gear?