I think this is an older post, but here I go. The suggestion for checking engine mounts, has merit. With very little room between the front mount and the damper pulley, a shift here would cause that clearance to close up fast. With almost 600 pounds of moving engine that could pinch the belt, pulley and front mount rather well.
Ok I got through that stuff. Water pump bearing..easy to check. Big 1 wire alternator? So maybe...just maybe, you have something shorting when you turn..right.
What is left? HRL gave you a good real time suggestion. A camera under the hood. Who would have thunk?
The question about the "funky" alternator mount, I did see that. Most mounts that work(yep opinion time) for me are the SBC truck type. Bolt to the head, and the water pump. The mount that was giving me so much grief...after market above the head and on the driver side. Very pretty aluminum heads, no drilled mount for the Alternator. Very pretty by the way. Chrome water pump, don't want to cover that up. and last but not least...STEREO. Amp is big enough to run my house. So he has 475 HP, in a 1930 chassis(no boxing, bracing, or help in sight). So..double pulleys and double belts.
