Is it worth doing this? Is there any benefit from it? I just boxed my lowers so I can add a rear sway bar. Just wondering if I should get some metal plate and box my upper arms as well. My neighbor wants to practice with his new welder. :)

The car is a driver on the weekends, not raced at all.

My goal is to make the car handle a bit more like a contemporary car. I'm going to rebuild front end and get new springs and shocks all around. I already have a 1 1/8" front sway bar and will be installing a 1" rear sway bar. Already swapped to power disk/drum set up.

Don't do it. The upper arms need to flex to reduce bind. If you box them, then all the bind is placed on the bushings. Your car will ride rougher, and handle worse.

Ok then...I won't waste my time. Thanks.