swap out the trans for a new venture 3500 5 speed manual od. it's used in S10's & full size 1/2 tons. or if you insist on having a granny low heavy duty trans. go with the nv4500 which comes in 3/4 ton & up chev. & dodge trucks. i believe theses trans. have a .68 od. with your 4.56 rear this would give you a final drive ratio of 3.10, excellent for highway use.
robert.
