Warmed-over 360+16 year old=too much?

I wouldn't go with a manual, for sure. For a kid , no matter how responsible , the temptation is gonna override intelligence. Stick gives you unlimited torque multiplication. Yeah a six w/ a 3 speed could easily drop a driveshaft. If you had a 273 accessible, I'd go that route. You can still get in a heap o trouble with that. Plus you mentioned having him involved with the process, that could and should place a little more respect towards the car as he has an interest in it vs. Being given something to thrash on. Good luck on whatever you decide.