Running down the hwy at my usual 75mph from a parts run... First I notice a slight loss of power but all feels smooth... Full throttle and only going 60mph so I let off the gas and then I hear a rattling sound... Then I see the oil pressure drop to ~30psi (mechanical pressure gauge--usually keeps 40psi on the hwy) and the temp gauge starts climbing... I completely let off the gas and pull over--the oil pressure drops to zero... come to a complete stop--engine's still idling smoothly but with a distinct rattle--oil pressure is zero--I shut it down. Engine temp continues to climb (up to 3/4 across the oem gauge) and some coolant boils over. Starter motor turns the motor over slowly... Buddy brings tow dolly from U-haul and drags my Scout home... Now that it's cooled off, the motor quickly restarts and oil pressure builds to 40psi but there's a definite knocking noise that weren't there before, and the oil is now black and burnt smelling (rotellaT 15-40)... I guess the next step is to pull the oil pan and inspect for bits and pieces? Is there anything I should do before pulling the oil pan like a compression test...? The motor was professionally (I got papers!) rebuilt in '97. So there's either 60k or 160k miles on the motor.