stock filter for sure. i use stock oil since its cheapest and i've had no issues so far.

I don't change my oil, I just wait till enough leaks out and then add fresh.

If anyone wants a hookup on MOTUL lubricants lemme know i get wholesale prices on it. Also word of the wise, most royal purple oils you get at o'reillys or some walmarts are racing only oil. This means they don't have any detergents in them, so running them for 5-6k miles will sludge your motor up. I tore a ls1 completely apart to clean it at 120k because the customer ran Royal purple its entire life at 5-6k intervals. If you're running royal purple, either switch to Amsoil/MOTUL or equivalent, or change it every 2-3k miles.

I have this available to me too but only at the dealership where I bought my car which is over 50 miles away so I never used my free changes (plus I don't want to run the risk of them putting well oil in my car). I changed my oil first at 10k miles. I bought the car with 3k and they changed it at the dealership when I bought it. So I ran it 7k miles before changing it myself to 5w30 Royal Purple. I just changed my oil again at 14k (3k miles ago). I plan on running this oil every bit of 10k miles though. I am on Amsoil and its great! I also changed to their filter as well as their Tranny fluid. I also changed over to 10w30 since we live in a generally warmer region and that weight of oil will work better with hotter ambient temperatures. Changing the tranny fluid is defiantly noticeably smoother with shifts too.

Amsoil is great shit! Just be careful with changing weights. As the motors age and sludge and varnish begin to build up in the motor, the small passages that control things such as variable valve timing, or oil squirters in the block that cool the pistons, they have a harder time pushing thicker oils. Even in 110 degree climates. From the few Ford briefings i've been to, along with other manufacturers that are starting to put more technology into these motors. When they say 5w20, they mean 5w20 lol. So if you start to have any issues with anything that is oil controlled, think about switching back to 5w20. After all they did spend endless amounts of money and man hours engineering the thing, I'd imagine they wanted 5w20 in for a reason. A lot of the eco boost motors are coming back with these problems, people take them to kwik kar and don't know any better. End up with bulk 30w oil or something and wonder why shit quits working lol.

From the research I have done the 5w20 is used basically to maximize fuel efficiency.

Yes thats partially true, but switching to 10w30 will have absolutely no effect on fuel economy. Now if you were to switch to a 10w40 or get nuts and go 15w50, yes i could see that somewhat affecting the mileage. You could probably get away with 10w30 for a while, but i've always gone with what the factory says to use, especially when they waste your time for 2 hours briefing you on all the new technological advances on their new engines, and how imperative it is to keep 5w20 in them lol. Same with the new GM lsx motors, 10w30 is almost mandatory in the dealership now because of the displacement on demand system, its so sensitive that it will shit the system down if a thicker oil weight is used because it can't function correctly.

The other issue is the tighter tolerances the newer motors are built with, which is another reason they recommend 5w20, everything is roller bearing as far as the valve train goes, so you don't need as much oil mass to pick up the slack in the clearances between moving parts like the old windsor 351s and H.O. 305s

There are tons of discussions on this on SVTP and other major Mustang forms about the oil I am using in paticular. I basically followed the guidelines of many people who are already running Amsoil 10W30. I am very pleased with it and the car runs fine. Just because it is a recommendation from Ford doesn't necessarily mean it's required or the engine will blow up. I have over 3k miles on the oil and couldn't be more happy.

Yea you'll be ok, just don't switch to royal purple and go 5-6k between oil changes, you'd be asking for it at that point lol. Amsoil is very remarkable shit indeed!

TurboZ, what will 7 quarts of 10w30 run me?

My bulk prices are in 5L jugs (almost 5.5 quarts). You'd be looking at close to $45 for a 5L jug, and then 2 extra Ls.

I'm going to used 15w-40 rotella in my stang.:challenge:

It'll be really clean! lol

go ahead and put diesel in it while you're at it. Oh make sure and use low sulfur so it doesn't foul the o2s :P