The 60E should be able to handle the tq but they do have a poor track record on even stock trucks. You could probably save a few buck by just having yours rebuilt to 65E specs. It should beef it up enough to be reliable. Not sure about all the specifics on the differances but I think it uses better planetaries and more clutches. HitmanX might know.
'02 1500HD, 6.0L, magnacharger, 2000stall, custom magnaflow with electric cutout, E-fans, Nelson custom tune, Auburn LSD.
'79 L82 vette, Summit 355, Dart Pro1 heads, Comp 274 cam, Holley TBI, Built TH350 with 2500stall
'93 Blazer, full size 2dr 4x4, new project.....