if you plan on keeping tractor and getting use out of your investment, I would go with the genuine CASE-IH overhaul kit. There are many other aftermarket kits available, but it seems like you always run into a snag with them that requires ordering more or addtional parts, or modifying or replacing parts from "universal kits" to make it all work. By the time you are done, you wish you would have spent original genuine parts price.
Just my personal opinion, go with a good Case dealer you like in your area for parts. This will also increase value of tractor if you go to sell it.
Of course Bez is correct, but crude ballpark for 6-cylinder diesel
overhaul kit about $2200. Thats the big kit, sleeves, pistons, lower main bearings, the whole shootin' match.( we just did a 1066 Diesel.) If the 504 is a four cylinder, or gas, or both, it may be less. If you do the overhaul, put in a new water pump and radiator hoses at the same time. It's too much investment to fry a new engine because water pump fails, and you'll have it apart anyways. If it's a diesel, you may consider new or reman injectors, depending how many hours are on tractor.
