Change leaf spring bushing...good idea or don't do it?

[Patsfan34]

I'm getting close to finally having my frame sandblasted. I noticed while stripping parts off of the frame, some...actually most of the leaf spring bushing are cracked and dry rotted and I would assume they are the originals. I would also assume that if I'm supposed to change them I should wait until the frame is blasted and redone. What can I expect if I replace them. Any tricks I should know? Can anyone recommend a good aftermarket company? LMC trucks probably? The frame is a 68 GMC 4x4 SWB.

Thanks,

Patsy