351M 10W-30/ 89 octane in the pan
got a 79 F150, drivin it last week, and it quit on me. pulled the stick out and found about a 40/60 gas/ oil mix when a few days before it was low a quart and very much straight oil. changed the oil and replaced the plugs (all 8 were oil fouled) tried everything to start it, ignition system, fuel system, timing, everything checks out but still no combustion. did a cranking vacuum test and got a fluctuation of 2-3 inches. thinkin it's either in manifold gasket, rings or valves. any ideas so i can no what to rip apart?