77 K10 Question 700R4?

[IPBuster]

Hello
I have a 1977 Chevy K-10 Camper Special Cheyene with a 6.6L SB400. It came with a TH350 hooked to a NP205 but my shifter works like a NP203 I have both 2 Low and 2 High and 4 Low and 4 High then Neutrel. But My question is I aquired a 700R4 from a 1989 Suburban 4X4 and i know that the transmision wont fit because i need the AA adapter and i have alrerady ordered it but do i need anything else? it came with the kick down cable and all the brakets to it. Plus i was wondering what is the durability of the 700R4 vs the TH350 I know the 700R4 prior to 1987 had alot of issues and Im thankfull that I got one from 1989 becuase GM corrected the issues with the 700R4 but is the 700R4 really a good transmission for a truck that sees offroad 4X4 use 8 hours a day everyday? I am a oilfield pumper and my K-10 is my work truck, I have put $4,500 into the motor ex bigger cam RPM air Gap Mainifold 750 cfm carb the motor was a complete tear down and rebuild with a few addons included to boost its performance, its pushing out about 400HP and 560 lbs of torq at the flywheel I have 4.11 axles, can the 700R4 take this kind of abuse on a daily basis? thanks for any help