[rpmerf]

Did the different starter work in the truck, or same thing?

Troubleshooting the starter on this is the same as on just about any small block.

Your starter has 3 connections
Ground to the block
Big cable to the battery
Starter signal

If the Bendix is pushing the gear out, that means your starter signal is fine. This means the relay and fuse are fine.

Here is where I would be looking:
#1 - When you turn the key to start and it clicks, what is the voltage at the battery? Do the lights dim down? Sitting voltage on the battery means nothing if it drops like a rock with a load on it.

#2 - Measure the voltage at the big lug starter. This should be equal to battery voltage. Again watch it with the ignition turned to start to watch for a voltage drop due to a bad connection.

#3 - I believe there is a fusable link on the large starter cable. If the big cable does not have power at the starter, this may be it.

#4 - I've heard of starters having bad spots on them. Forget what the actual issue is. If you can rotate the starter a bit, it will work.