You may need to get a tail shaft and an adapter...To be honest, it has been a long time.

I will be with my dad later this evening, I will ask him, he will know of the top of the bean what it would take...

GT

when I put a car 350 trans in my Blazer it needed a new output shaft, shorter

I think  after  reading all this  you will  keep the th350 and np-205.

Heres the kit P/N 50-3202) GM TH400 to NP205 with figure 8 bolt pattern adapter assembly. This kit replaces both 10 spline & 27 spline male input shafts.

Transfer Case:
GM NP205 (10 Spline)
GM NP205 (27 Spline)
Transmission:
GM TH400 (2wd)
  Price:  $627.21
The np-205 will have to be machined for the larger output bearing.
And  like  HD said thats  new drivelines and crossmember will also need to be moved. and mods to the  floor to clear the shifter.
 You  can read all the info here http://www.atlas-tc.com/pdf/50/50-3202.pdf 
 

Huh, maybe it was the gear in the transfer case that had to be changed. I remember bringing the transfer case home in the car, it's been a while (1990. I had the trans built too at the same time so I really cant remember. When I was in school I assembled a t350 in under an hour. T400 in 1hr 20 min. The t350 can have clutch discs added increasing surface area by about 20%. You have to turn , i believe it's the clutch basket piston, I did it on a brake lathe. Again it's been a while.

My old 3/4 ton 4X4 1976 Chevy came with a T350 and a 350 small block....


Before I pulled the automatic I built a 468 big block and put it to get things running with the T350, I pulled the daycruiser to the lake, the car trailer with dad's '57 Chevy, a 28' Hatteras to the bay among several four wheel burnouts, it had a 6" lift and 36" tires with 4.56:1 gears, never broke the tranny, sold it to my bud who put it straight in his full sized Blazer....Then I put a granny four speed in the truck....

You cant miss with a turbo 350, great stuff...It take 15 more hp to turn a 400 vs. a 350 BTW...

Get some TCI parts in it, hardened pump rings, bigger pan and a cooler. you will not break it.

GT