Ford recommends 5w-20. I run what came in it from the factory, 5w-20 MotorCraft Syntec Blend. M1 is good oil, but its extremely thin, almost watery, and isn't necessarily the best motor oil for every engine. Some cars like it, some don't, but mostly it really doesn't make a difference. I had a 280z back in highschool that I ran M1 in for awhile. My oil pressure would drop to 0 whenever the car was idling. Switched to a heavier oil and the pressure held. I've used the factory oil in all three of my Machs without any ticking, etc. However, I have had other noises creep up. Mainly exhaust leaks and drivetrain noise. The shaker will also rattle on some Machs as well, nothing to be concerned about. All engines tick a little internally, the LS1s downright knock on warm up (most of them), but its normal. My S197 sounds like the entire valve train is coming apart (not really, but its audible), lol. Unless it is very apparent, blowing smoke, burning oil, or losing power, don't sweat subtle engine ticks and knocks too much.

 

I get my oil changed at Ford. 11.95, and they use 5w-20 semi synthetic. It burns about 3/4 to 1 quart between oil changes. But has lost no power.

 

im going to be swapping to Amsoil soon. when i can afford a $100 oil change... they seem to have a far superior product than off the self oil.