Delco Starter Problem

[danzee]

I'm working on an A4 in a '78 Catalina 27. Symptoms were no action or a dull thunk when the key was turned to Start. The starter is a Delco.
I found the key switch to have a large voltage drop and some other connections to be less than ideal. I replaced the key switch and cleaned up up all the high current positive and ground connections between the battery(s), motor, and starter solenoid.
I also added heavy gauge wires between the starter switch and solenoid, sistering the harness and connector, in keeping with the Moyer wiring kit instructions.
Now the solenoid makes a loud clack when the key is moved to the Start position, but the motor still does not spin. The clack sounds to me like it is full stroke and that the starter fork is being moved. Voltage drops are low and more than 12 volts is maintained between the the solenoid positive post and motor ground during the Start attempt.
I intend to pull the solenoid and examine it's contacts. I'd like to isolate the problem to starter or solenoid before I order parts. I assume I will be able to examine the solenoid internal contacts and see if they are the problem.
1 - Anything else I should look at or do?
2 - What is the current path from the solenoid Bat post to the starter windings?