Overdrive trans or change rearend/gears

[longbed67]

I think the biggest question to determine is what is his budget... If he is on a very limited budget he could just switch his rear to a 3.07 or 3.08, but taking off and general drive-ability would suck, and fuel econ would suffer even more. However you can pick up a sm435 or np465 4 speed pretty cheap with the granny gear first and the 1:1 final, and with the 3.07 rear swap out you would have good drive-ability, better hwy rpms, a fairly stout tranny, he wouldnt have to swap the trans crossmember or the clutch or any linkages, and all said and done he would have less than $400 in it.