A friendly suggestion while you have it apart is to consider replacing the crankshaft with a forged 6.1 crank or aftermarket crank. The forged 6.4 crankshaft would also probably work, but I would double check. It would be a different stroke while the 6.1 is the same. The stock rods and pistons are the weakest part of the rotating assembly. If you can, I would replace the stock powered metal rods and fragile pistons with forged high quality components. Just my 2 cents.