Funky wiring

[Chumley]

Just got a '72 Supreme. What should the positive battery cable look like as far as design? The cable over heated trying to crank the engine , so I pulled it and it was pretty fried down by the solenoid. Also, someone spliced a piece of negative cable on near the battery post. There is no wire going from the positive post to alternator like on some other GM motors, however there WAS a wire going from the solenoid end(as part of the positive cable) up to a relay of some sort which is mounted on the firewall above the distributor, which has a few other wires connected to it as well. It seems as if there is no charging going on, which would explain the alternator light staying on and slow cranking speed( sort of like a Mopar with a cam). What should my new battery cable look like? I'm also going to trash the old engine harness and replace it. Did that on my '72 Chevy and it solved everything. Any good resources for a new harness with HEI conversion built in? Thanks, Chumley