Luke@MillerPerformance
Member
I just pulled apart an 04 with 300k miles. One head cracked after it plugged the 5th oil cooler Ford had installed. Never did a coolant flush or installed a filter. Truck had ARPs with OE gaskets. Water jackets were full of rust and other junk. Tore it completely down, had the block fully cleaned, new bearings, new rings, new lifters. Block was still nice and flat.