I have a 4.0L 6cyl '98 Jeep Wrangler that has 290,000+ miles on the engine. I'm going to start to rebuild here soon on it and fix up a lot of things that have stopped working. I have about every tool under the sun and a lot of time on my hands. Would it be better to just rebuild the engine (no experience) or by a new, rebuilt, or even a 4.7L engine? If I got the 4.7L would I need to change the set up I already have for the current engine? Thank You!

 

I would keep with the 4.0L. As you see from your mileage, they are great engines. You can get a used one from a wrecking yard for a fair price. I really miss mine. I have the 3.8. Runs great but goes thru oil fast and I only have 54,000 on it. good luck!