Thanks for the replies.
Sounds like the best course to take is to refurbish the drums, and see if I am not happy with the results, before I convert to disk brakes.
I was able to lock up the rear tires on my pickup, and it happened quite easily. I never tried to get the front tires to lock up - didn't seem like a good idea. I never noticed any fade. I was running Coker bias ply tires which seem to have poor traction.
The Suburban has better weight distribution and will have radial tires, so I am anticipating better stopping even with stock brakes.
