My only concern would be the electronics on the transmission, the 4L60E is a completely different animal even though they use the same nomenclature (4L30E, 4L60E, 4L80E etc). If it is just a few connections then it's not a bad idea, but you could also use a 700R4 (early 4L60E) from behind the 2.8 V6 S10's and adapt a t-case or use a stock chevy case. A Planet member did this with his 3.2 and used a Dana 300 case with twin-stick shifters. The issue with this swap though is even with the small Dana 300 case, the tcase rested on the torsion bars just a tad, he had to cock the transmission slightly to cure this (drill a new hole in the crossmember and push the transmission to the side a tad to line up). If you used this tranny you'd have to fab up a bracket for the TV cable but that's pretty simple. Main advantage to that one would be no wiring really needed other than hooking in the speed sensor. You'd have to figure out the transmission wiring on the 4L60E from the H3 and also the tcase wiring (since they use a push button system)