Can i swap a 2.5l to a 4.0l jeep engine? If yeah.. What i need to swap a 4.0l? And is there any mods of my motor mounts and can i use my 2.5l 5 speed transmission?

 

why not to a 3.9 v6 like the ones that already come in a dakota or if your going threw the trouble of a swap just do a 5.2 v8

 

What kind of mods i need for a v8 swap? How much money will i spend?

 

This seems to come up every now and then. Its something that I'm actually looking into. You will most likely have to fab up your own engine mounts. As for the transmission, yes it will work. Jeep 4.0's came with the ax15 transmission stock until the 00's. HOWEVER, there is a different in the input shaft on the Dakota's ax15 than the one on the jeep. The Dakota one has a 14spline 1inch shaft, and I believe the jeep one has a 10spline 1.25 inch shaft. You will need to find the correct clutch disk for this.

You will need to locate the engine (obviously), the flywheel, clutch assembly, and the bellhousing. I'm unsure of whether your stock clutch slave cylinder will work.

I have read that the jeep 4.0 is 1.5 inches longer than the 318 motor, so I am sure it will fit fine. You may need to install push fans for extra room though.

You will also need the engine's computer and all the wiring (unless you decided to go custom with Megasquirt or something). This would probably end up being the most daunting part of the swap. However, you may be able to find resources. Go google search "jeep 2.5 to 4.0 swap". People do this swap all the time, but on jeep wranglers. So it has been done, just not on a Dakota.

I would say, however, that unless you are hellbent on doing this, I would just get a truck with a larger engine or learn to live with yours.

Edit: I noticed your location is California. I now change my recommendation to "just get a different truck". California has crazy emissions laws, and while it is still possible to do engine swaps, there are critical inspections they do to guarantee everything is safe and up to spec. The engine must be from the same year or newer, and all the emissions systems on the donor engine must be preserved.