454 Throttle Hesitation/Vacuum Leak??

[tucsonjwt]

I always suspect the carbonator. Are you sure that your choke is open all the way when the engine is warm (which won't take more than one minute in the summer?) I would remove the air cleaner when the engine is warm and make sure that the choke valve is in the full open position at idle, and yank the throttle to make sure that it stays open under moderate acceleration.