GM-GMC: 77 chevy p/u driveshaft issues, driveshaft, yokes

Question
i got a 77 chevy p/u and it came with a single shaft with the bracket for center support bearing cut off. it vibrates at 40mph and a light grinding noise when letting off gas at that speed, should i try to go back to the original driveshaft im pretty sure its suppose to have or would it be easier to get a bigger longer shaft with replacing yokes and u-joints?

Answer
well the noise you are hearing is definitly related to the parts you are talking about and i always recommend using the original equipment unless you are modifying the other parts to handle what you are trying to do.

if you replaced the shaft with one that is not the original then you should either change it back or change the ujoints to handle the shaft you put in it.