Slow cranking 70 GMC Help

[70gmcfs]

Hey everyone, I just bought this 1970 GMC C15 and starting to do some work to it and get everything working right. Right now I'm trying to figure out why it is starting up so slow, it has been like this since I got it. It is a 307 with a 3spd that was on the tree and I converted it to the floor, still has the points system and external voltage regulator. The points all look brand new, same with the spark plugs and spark plug wires, I just put a new coil on it as well. The battery cables don't have any corrosion on them, however do look old(going to be replacing them). I was looking at the solenoid and there is one wire that is on it and it looks like somebody stripped a wire to put that one as well or it fell out of its connector(can't tell what the colors are yet). Is there supposed to be two wires going to the solenoid on this? Could that maybe be the issue? Any help would be greatly appreciated. Thank you in advance

P.S. this is an awesome site. Very Helpful

[geezer#99]

THere should be 2 wires on the solenoid. Left one is a purple wire that goes to the S terminal. It comes from the ignition switch. Right one should be yellow that goes to the I terminal. It runs to the coil.
When you turn the key to start the motor, power is sent to the S terminal from the ignition switch. THe solenoid pulls in, the starter cranks and your motor starts. Also when the solenoid pulls in a connection is made inside the solenoid and 12v is supplied to the coil via the yellow wire. You need 12v to the coil for starting only. When you release the key, power is shut off to the solenoid and then power from the ignition switch to the coil comes thru the resistor wire to the coil. Voltage is reduced to about 7-8 volts. You can't run 12v to a coil all the time or they overheat and quit.
If it cranks over slowly then definetly replace the battery cables. You need clean connections and good wire for cables. They may look good but can be corroded inside.