The B230 engine systems are pretty simple compared to today's stuff.
First thing, the tow truck operator is probably assuming it is an interference engine which would not crank with a broken belt due to the mechanical stoppages (and major valve/piston damage). This is not the case with this engine which is non-interference. The tow guy is a tow guy for a reason, not yet ready for prime time in a shop.
Poor running is traceable to numerous things which can be checked with minimal tools.

1-a small oil leak into the distributor will screw things up quite well, as old as the car is the oil seals into the dist may be shot, check that first along with the cap to see if there are any tell-tale arc points on the interior surface, those would indicate misfires

2- old spark plug wires can be arcing onto metal engine components or into each other, check them out on a dark night to see if there are any sparks visible (use a wooden stick to move them around, there will usually be a tell-tale surface anomaly where arcing is occuring if a bad wire is laying against a metal part such as the valve cover)

3-the power stage is a possibility, I always grab one or two at the pull-a-part to keep in the glove box, they rarely go bad but will cause havoc when they do

4-the AMM is not likely but possible, check it as said in an earlier post

5-If the timing belt is as old as you say and it has never been re-tensioned it may have skipped a tooth, recheck the timing marks on the gears (needs the upper belt cover off to do so) but beware, if the crank pulley has slipped (another old part issue on these engines) your crank position may not be accurate if using external timing marks of the pulley & lower belt cover

80 AMP is plenty for your vehicle if you did not add any heavy draw electronics to the car

Post back with your findings