need help choosing transmission

I just built a 350 chevy motor (about 430 h.p.) for my 87 1/2 ton 4wd chevy pickup. It has a stick in it and I would like to convert it to an automatic. What automatic transmission will work best with my transfer case? Any suggestions?

I would look for a TH350 if not, you can use a 700r4 or a 4l60 (700 and 4l60 are the same basically) will work but you will have to do some serious beefing up if you want to use them for severe use.
You will have to find one that has the correct output shaft and extension housing to work with your transfer case