Slow Crank, No Start When Warm

What I'm going to be saying I know as personal fact. My dad had a 1981 dodge pick up and he had issues with starting when the engine was warm and a charging issue as well. I replaced both battery cables, checked all wire connections for being clean and tight, only a temporary solution. I put on a starter for a 440 ( his truck had a 318 ) and it helped for a while and then one day while I was trying to figure it out I noticed a braided cable that was bolted to the firewall but the other end went no where so I decided to bolt the other end to the block and problem solved. So I decided to do some research on this and I discovered that a ground cable has to go from the battery to the block, and from the block to the firewall. I don't know if this was factory or not but it also had a cable going from the frame to the block. I don't know if this will be of any use for the OP, but I hope that maybe it will be of some help to someone else. Also I've seen both battery cables corrode inside the cable. No one told me this and I didn't hear about it from anyone, it's from personal experience.