J and K AUTOMOTIVE TOWING AND REPAIR 3/19/2011have you checked your transmission fluid level and the condition of the fluid
HouseCallAuto 3/19/2011Sounds like a clogged catalytic converter. 1975 was the very first year catalytic converters were used as an emission control device, imagine that. Confirm this by removing the oxygen sensor temporarily just for a road test. if the power comes back SUBSTANTIALLY then you have diagnosed the cause. Then buy a replacement converter and replace the O2 sensor at the same time.
Another cause could simply be that the ignition timing is way off, too far retarded. Check the timing first, even before doing the above. Also, after verifying that the timing is good, replace the inline fuel filter in the carburetor. they are very small and often become completely clogged and block the flow of fuel causing severe hesitation. Thats all I got for now.