Probaly the only thing that will need to be changed is the length of your drive shaft. Usually a 700r4 is longer than a turbo400.
Also, the slip yoke on the driveshaft for the output shaft on the TH400 is larger in diameter than the 700R4.
You will need to install an electric kick down switch in the throttle linkage for passing gear on that TH400.
As long as its an automatic. You prolly have either the 700r4 or a th400. there are many shift kits for both
Yes you can.
Yes
You can if the 1990 truck is a 4x4.
no it will not fit at all
Any automatic trans from Buick, Oldsmobile, Pontiac or Cadillac will bolt right up. A Chevy transmission will NOT bolt up without and adapter. If you change from a TH350 to a TH400 you will have to change your drive shaft yoke and the cross member. Unless you just have one lying around, or find and extremely good deal on one, there is just about no reason to put a TH400 behind a 301.
No simply put 2 speed powerglide= 2 gears a 700r4 has at least three and some have overdrive.
Caesar did not put Senate benefits in place.
Yes you can it will bolt right up to it.
yes as long as it is not the 350C lock up convertor and have or need the right stall for your needs.
assuming the fluid wasn't low when changed, approx 4 quarts. add almost 4 then check the level.
No.. 2-wheel and 4-wheel drive transmissions will NOT INTERCHANGE