Hesitation is usually wrong timing or busted accel pump diaphragm in the carb, or blocked accel fuel passages. Take off the whole air cleaner, and while manually holding open the choke, look for a steady stream of fuel from accel jets in carb bore when you manually open the throttle wide open with the linkage. May also have worn and hanging centrif advance weights in the distributor.

Have good accel at higher engine speeds? Many of these carbs have a bad secondary throttle vac can enabler, and the second carb barrel won't open. If you have this, post back and we'll tell you how to test.