Just an FYI, the 98-2002 24 valve engines did have their problems. I know, I have owned 3 of them. The biggest deal breakers are as follows: Check to make sure the engine is not a "53" block. The 24 valve blocks that have "53" in the block casting number, which is found on the passenger front side of the block. These blocks are known to crack open, along the coolant passage, even in stock form. This crack parallels the exhaust manifold. Second, these engines have a huge achilles heel problem. The VP44 injection pump is half electronic, half mechanical. There has been no way to make sure that the injection pump will last. What happens is that the electronic lift pump pulls the fuel all the way from the tank. The lift pump is mounted on the engine block. The factory lift pump cannot handle the job. When you drive the truck hard, the lift pump starves the injection pump (Which is cooled by fuel, not oil, like the previous years). All it takes is one time, or a 1psi drop in fuel pressure, that takes out the injection pump. If you are new to diesels, the injection pump is like the distributor and carburetor all in one. It handles engine timing, and fuel delivery. With the amount of miles on the truck, I would plan on installing a new injection pump, and a new aftermarket lift pump. Most enthusiasts install a fuel pressure guage in the cab of the truck to monitor that delicate and sensitive injection pump. Installed, the injection pump will run you about $2200. All of my 24 valve trucks blew up between 150k-200k. Good luck! Personally, I would stick with the 94-97 12 valve cummins with the P7100 injection pump. time has proven that motor to be indestructable and ridiculously efficient.
