I have a 283 in my 61 4x4, it does ok. Its a good little reving motor, but that 400 will have more torque than the 283 in a 4x4. I had a sm 420 4-speed in my truck and the 283 did good. Then I changed it out for a th 350 auto, and it sucked the power out of my little motor!
But anyways thats my 2 cents.