I did an oil change on a '95 Ford F-150 over the weekend. It has the 5.0 V8 engine. I looked in the owner's manual and it stated 5 quarts for the engine capacity so that's what I put in it. Started it up, everything sounded fine, but I made one crucial mistake: I forgot to check the oil level. I called them back and had them check and they told me it was at the full mark but I don't know if perhaps he didn't check it right? I now read on Amsoil that it takes 6 quarts with filter, and I'm wondering if the manual actually said 5 quarts WITHOUT the filter, and I should have put 6 quarts in? Does anyone else know about this and should I call to have them add another quart?