Hello, I recently bought a 2007 F-450 with 452k miles. This truck was used mostly for towing. I was told it had a lifter problem and possibly the camshaft was bad as well. Took off the engine and removed the camshaft and one of the lobes is in fact rounded off. My question is that at this point should I do an overhaul on it (pistons,rings,bearings, etc) or should I just install the camshaft, bearings,and lifters? Took off the cover and pistons look in excellent condition, but I have not disassembled that portion of the engine yet so don't know in what shape the rings are, etc.