my cousin got an F-150 with the bulletproof 300 4.9 I6, very low miles for the year (113,000 miles). truck is rough though, no cat or muffler and had sugar put in the gas tank one time, and just overall beat up bad. runs excellent though. so due, to the low mileage, it would seem wise to use a top quality oil and filter, but my cousin is on a budget,and dont wanna go too expensive with the oil, and still relies on this truck day in and day out. so would it be best to use a 30 wt, im thinking 10W30 pennzoil and a napa gold filter, or a 40 wt? what do these ol 300's like best? i hear they run and run as long as they have something sloshing around in the crankcase lol.