Could have knocked the smaller "hot" lead loose where it connects on the same terminal as the larger battery hot lead (usually at the starter solenoid or stomp-starter contact, whichever you have). Also check the connection(s) at the coil.
It never hurts to replace plugs & wires but you could do alittle more troubleshooting 1st.
With the engine idleing, use an insulated pair of channel locks or pliers and pull one spark plug wire off at a time. Each time watch/listen for a change in engine speed. The engine should start missing on each removal. If it doesn't you've found the problem cylinder. It could be a bad plug, wire or something else like a valve not closing etc. Odd's are it's the plug or wire...
Generally if one plug is misfireing (or plug wire) the others are then suspect and replacing all would be recommended.
Trace all your steps when you changed out the large battery cables and be very observant. Sometimes it's all too easy to knock something loose on a repair and then theres always the probablility of something going bad just by coincidence when you repaired something else. As they say stuff happens.
Good luck
Dave
