As it turns out they were the right ones. The U-bolts I ordered are about 3/4" longer. I'm pretty sure they'll work and have enough threads.
I used Denny Graham's method of spring bushing removal. It worked great, except for the last one. It turned out to be a multi-tool event.
Body say, die grinder, hammers, punches, screwdrivers, bench vise, electrical tape, and curse words.
