**r*a*n*t**

Just depends on intended use...I got the 8 1/4 in my 340 Dart Sport and if I keep it under 450 HP it will last just fine. Good rearend much better than "most" think. and I dont care about gear interchange.I don't race it so anything between a 3.21 and 3.55 or the equivalent is fine and would STAY in place..im happy with the 3.21 SG right now in it. and unless I go racing which is not happening its the 8 1/4 and if this one happens to go bad just becuase of age and I had to replace it ..unless I find a Dana or 8 3/4 already for a A body sitting around for the EXACT same price as a 8 1/4 im getting another 8 1/4!