Atransman wroteIt really depends on what you plan on doing with the vehicle. If you plan on rock crawling go with the NV4500. The NV4500 has either a 6.34:1 or 5.61:1 first gear (depending on the transmission) and the 700 has a 3.06:1 first gear.
The downside to the 6.34:1 chevy nv4500 is it was only made for 2 years and 1st and reverse are not syncronized.
Depending on what route you go with adapters the dodge NV4500 uses a 9 1/4" long input that is 1 1/4" in diameter and the Chevy input is 7" long and 1 1/8" in diameter. on your long wheel base vehicle this doesnt mean much but it is something to keep in mind as the dodge input is significantly stronger.
also the dodge tranny's up to 97 or 98 in gas powered vehicles had a 23 spline output. The dodge diesel's use a large 29 spline The chevy's use a 32 spline output.
The later 96 and up chevy nv4500's use the same gear ratio as the dodges but require a input bearing retainer with a collar as they are designed w/o :!: IIRC. as it was not a big problem. also the early chevy nv4500's have a different bolt pattern for marrying to the bellhousing than the later ones. the later ones share the same pattern as the dodges.
I vote for the nv4500 just be aware that with a dodge input you will have to order a special clutch with a different hub to match. easily done just specify. and if you have the linkage and bellhousing i would do a dodge NV4500 matched to a T176 or T18 bellhousing using your existing linkage etc. If you dont have the linkage i would get the AA bellhousing and either the chevy or dodge nv4500 and then you will have to put the chevy input into the dodge and machine down the input collar. and run a hydraulic clutch. the benifit here is a t-18 clutch for a J truck works
i changed the output in my dodge nv4500 from the big 29 spline to a 23 spline output this also requires a different OD gear both parts were not that expensive and eaily had through inland truck parts up in missoula mt.
As to the 700R4 Paul is right the torque converter does compound the ratio and the 700R4 has a low 1st gear to begin with lower than some other auto's out there. and i believe the number is 20%-25% of the power is lost to parasitic drag correct me if im wrong here. but it is a nice easyt o come by setup. the build up that is necessary to make it last with the torque of the 401 is expensive but well worth the investment if you choose to go that route. dont trust most run of the mill kits nor shops. the 401 shreds these things just like a 454 does when they arent done right
