Well, I decided that as a man in Texas I needed a pickup. I got a '95 Dakota 4x2 with the Magnum 3.9 V6 175hp engine. I got it off my FIL, who is almost on a BITOG level of obsession about maintenance. It's been very well kept and is in excellent condition. It has 165,000 miles and has had the oil changed with only M1 10W-30 EP at 5k OCI since new. It has a one gallon sump. Mobil 1 filters were favored, but other brands were used intermittently. I plan to use the M1-301 filter from this point on but if you can suggest a better option, please do. The reason I'm posting here is because I thought it might be a good idea to switch it to HDEO considering it's age and mileage. Also, I'll be towing a small boat and doing some light to medium duty hauling of things from time to time. Any ideas? I was thinking a 5W-40 might be in order but I'm open to suggestions. No idea what a good OCI would be. Keep in mind I'm down here in Texas and it does get a little warm for most of the year. Cost of the oil is not a factor but availability is. I only use oils that can be bought off a shelf without too much searching.