I have owned 3 V10 Rams and know a number of other owners from other forums like DodgeOffroad and PavementSucks who give many opinions. Overall it's a decent motor if you take care of it. The spark plug wires need to be routed carefully and per instructions to avoid cross-firing and other than the early head issue the only other thing I know of is making sure the front cover is properly torqued. The oil pump is very unique and rides inside the front cover, so any loosening of the bolts can result in damage to the cover. They were special styrofoam cast in sand units and there are no NIB replacements, only leftovers at the salvage yards. Mine get consistent 9-10mpg regardless of empty or loaded with an automatic. I'm easy on my trucks and use overdrive lockout consistently until I get on the highway at 65 loaded. I feel like my trucks prefer running just at or around 2K rpm in OD to have consistent power and avoid kicking in and out of OD. Best upgrades for the auto are replacing the plastic accumulator and other plastic parts with inexpensive aluminum units, getting a conversion kit to run the Chevy solenoid, oversized pan, good cooler and temp gauge. A simple mild shift kit doesn't hurt either. Check your gears as well, as 3.54s are common and I'm running 265/70R17 3rd gen alloys and need the 2k RPM like I mentioned above to stay in OD.
You'll likely have a D70 rear, which is a decent unit, but you can swap in D80 or AAM 11.5 if you want something larger. If you change out the muffler, go with a large unit like the Flowmaster Big Block mufflers or it'll sound like a lawn mower or ricer. There are a ton of aftermarket headers on Ebay that are okay as long as you have a local shop verify the flanges are flat. The air intake system from K&N is worthwhile, though expensive. You can make your own kit from some of the other filter makers DIY options. The V10 bellhousing is the same as the Cummins, so starters and trans are direct swaps more or less, which makes for easier manual swap if you choose. Motor mounts are almost always bad, believe there is a poly option available and it's likely the same kit as for the Cummins. Radiator is in between the size of a V8 and Cummins, but the radiator support is setup to handle the larger radiators if you want. I believe Griffin makes an aluminum version.
My 2003 V10 is a crew cab and the last of it's breed, so I'm hoping to run it for a long time. I plan to have DTT rebuild or at least use their parts after lots of research. You don't need to get the crazy expensive upgrades unless you're really hard on the truck. I plan on adding an aux trans filter and dual trans gauges to really keep an eye on temps. Can't really think of much else....I have a build thread on my '98 V10 on another site, but need to see which one. I removed the original V10 and swapped in one from my 3rd wrecked truck and completely went through the motor with new gaskets, water pumps, etc, so there are some good pics to show how everything goes together. Yanking those motors is NOT FUN!! Easier to pull the engine mounts off the block than pull the intake IMO. Feel free to ask if you have questions!
