84 GMC Jimmy K1500 tranny swap

[Suicide-D]

I have an 84 GMC Jimmy K1500 with an NP208 transfer case and a manual 4 speed transmission. I have recently dumped a 350hp (estimated) 350 in this and I really have to get the rpm's up too get going. It has a 3.08 rear end. The tranny is a 4 spd, but the 1st gear is really low range and I have to shift to fast so I dont use it. Will changing to an automatic help in this area? I have a turbo 350 I can have rebuilt...What would be necessary for me to mate a turbo 350 to my transfer case? Thanks