Can a torque converter out of 350 Chevy work on 396 big block?
No, a torque converter from a small-block 350 Chevy will not work in a big-block 396 Chevy. The input shafts are different diameters and the overall dimensions are incompatible. They won't even bolt up. You need a torque converter specifically designed for the 396 big-block Chevy.