Risks of Running High Amp Alternator?

The 1963 and 1965 Mopars have dedicated buss-bar feed-thrus in the bulkhead for the thick ALT (blk) and BAT (red) wires, unlike the "56 terminals" (spade) of other years which melt. Still, I wouldn't send >70 A thru the dash ammeter since any corrosion at the screw connectors could overheat, plus the ammeter isn't ranged for that. As stated, you can just run the ALT output straight to BAT+ in the engine bay. The 5.2/5.9L Magnum engines do that, running across the top of the timing cover.

I did that, using a Magnum ALT/BAT harness. But, I installed back-back 200A diodes in that path so the normal path is thru the ammeter until >0.3 V drop in that path causes the diodes to start shunting current directly to the battery. That keeps my ammeter active. Search my post "Modernized Wiring ...". But for most people, just live with a dead ammeter as all modern cars do. You can use a cigarette lighter voltmeter to monitor while driving, as I do in my modern cars. If you see >14 V, the alternator is outputting fine, so no surprises at the next stop. Someday, when the cluster is out, you can install a voltmeter in place of the ammeter.