Classic/Antique Car Repair: Wiring of 1976 buick starter, solenoid, interchange

Question
I have a 1976 buick 225 with a 455 engine and have taken off the starter - when  reconnected (three wires) the car runs without a key and drains my battery. I am unable to find schematic for the starter to get wires on correctly - can you help?
Thank you

Answer
The big wire goes to the largest terminal at the top of the solenoid. One of the two smaller wires should be purple and it should go to the start terminal of the ignition switch and carry voltage only when the ignition switch is turned to the start position and is connected to the "S" terminal of the solenoid. Both small terminals of the solenoid should be marked, one "R" and one "S". When looking at them the "S" terminal is slightly larger than the "R" terminal and the nuts will not interchange. The other wire comes from the + terminal of the ignition coil and is connected to the "R" terminal of the solenoid. If this does not do the trick let me know and we will go from there.
Brad