NP435 and transfer case questions

[broke_okie]

I have a NP435 married to a Dana 21 transfer case in my 71 f100 4x4. I want to bolt up a NP205 to my NP435.Iknow my NP435 currently has a 10 spline output shaft, I know the NP205 requires a 31 spline shaft. Is this all that I need to change for the swap? If so can you direct me to companies that sell the proper output shaft for this swap?

[Rockcrusher]

I believe the bolt pattern on the back of the NP435 is different also.

If I'm not mistaken, the 2WD, 4WD/divorced transfer & the F-100 4X4/Dana 21 transmissions have a rectangular bolt pattern. The NP435/married transfer units have a trapezoidal pattern.

[heep70]

Rockcrusher is correct. You can't put a NP205 behind a NP435 that had a D21 on it. You will have to find a 435 that has the trapeziod bolt pattern or a 435/205 already mated.