Now, i need to put my 2 cents in, I put a 56 235 in my 46 1/2 ton with a T-5 and a s-10 rear with 308 gears and 235-75-15 in tires and I have no issues at all with RPM or speedometer, I pull a teardrop trailer on the interstate and back roads and hills like im in a new modern truck, of course certain size hills,im gonna have to downshift, but im not climbing huge mountains either ......