tranny and t case woes

[1BAD77K10]

hey everyone,   got some questions about doing a tcase swap and trans swap.  my truck right now is set up with a sm465 with a np205.  i also have on hand sittin in my shop a th350 with np203.  the truck is gonna be a mud racing street truck.  and the 4 speed while fun to drive and extremely strong is not favorable for racing.  the question that i have is can i take the the np203 off of the th350 and replace it with the np205 from the sm465.  the th350 np203 is from a 79 and the sm465 and np205 is from a 77 chevy.  i want to keep the np205 but want a automatic.  the trans that i have is fully rebuilt and race ready so i would rather not let it go to waste.  if anyone needs anymore info on either combo just let me know.  thanks

[Blazin]

Output spline count on the SM465 is not the same as a TH350. You would need to replace the input shaft of the NP205 with the same spline count / size as a TH350.

[Irish_Alley]

or find a 205 off a th350 the sm465 will have 10 splines and th350 will have 27 the only 205 that has 27 splines if off a th350