I install a matching 400 engine and tranny in my 53 stakebed. runs really smooth up to 2500 rpms, if i go any faster i get a vibration in the drive train. i had a driveshaft made and thought it was that so i had another one made and put new ball joints in. could it be the rear end. it shifts good, no noises just a virbation, used tires but they were spin balanced and wheels are not bent, any suggestions. i plan to put a 301 ratio in in the future, also if i do put the 301 in the truck should i have any problems, would it be geared to low?thanks for any help. i think it gets up to about 40 or so before it vibrates.
