Kahn,
Rich has it right, however there is another way. If you buy an aftermarket starter with a built in solenoid you can eliminate the solenoid on the firewall. Also with a 1 wire alternator, you can eliminate the voltage regulator. This will simplify the wiring a bit also. If you want to keep it old school, I bought the parts, but never used them. Two regulators, one new style, and one that looks old style, but has the new style electronics in it, a solenoid, and an alternator. If you want them, they are pretty cheap!
Brad