All OEM equipment did overheat connections in wiring, back when it was all new. Most dangerous scenario was/is jump starting a dead battery. Start the engine with choke set to high idle and the alternator will send all it can through the only path to the battery. You have all new connections going to a 50+ year old amp gauge. That gauge may be your weakest link.
Adding one wire from alternator to starter relay stud does render the amp gauge inaccurate but it takes the high amp charging load off of it too.
