I would definatly go with a Dana 60. The Ford 9 inch will not survive behind that motor in stock form, but the Dana should. Don't the new Cummins Dodge 1-ton trucks use a Dana 60? The Dana 60's are surviving in the back of trucks that are putting out 500+lbs of torque in a near 20,000 lb vehicle when towing a trailer. From what I have read, a stock GM 12-bolt is actually stronger than a stock Ford 9-inch, but the 9 can be made a lot stronger than the 12 for less money due to its full floating axles and the design of the casing.