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Start with the basics. Basically a tune up. Usually a good idea to do on a vehicle that is unknown, new to you. The hesitations you mention might be tune up needs.
Pull check/clean/gap plugs.
Check/clean/adjust Points gap.
Check that at full spark advance the distributor upper plate arm is against one side of the Distributor body opening, and at full retard the arm is against the other side of the distributor opening.
With spark set at full retard, check/set timing via the timing pin method.
Remove throttle linkage at the carb, manually exercise the Throttle plate - check it is free and goes completely open and closed. Re-attach linkage and insure it goes completely closed to completely open via the foot pedal.
If the vehicle is a pickup, it is possible it may have a 4.11 rear end, which reduces top speed. Typically cars do not have a 4.11 rear end.
Depending on your experience level, at this point you may want to find someone with experience help you. Start with the basics, so they can be ruled out.