I've heard the 3.9 L is pretty under powered. I have to do some work to this pickup before it's road worthy anyway, so I was thinking of swapping the 3.9L for the 318 v8. I've been told my standard tranny that came from the factory will bolt onto the v8. I'm also wondering if I will have any other issues like the computer or wiring not attaching.
I have a local you pull wrecking yard in my city that I'm planning on getting the engine from. What other parts should I be sure to get? My Dakota is the lowest base model. Will I have an issue if the motor comes out of a higher end model like an Sport or a Sxt.

 

The engine is the same regardless of model. You will need a PCM for the 5.2.

The transmission will bolt up. Both the 3.9 and 5.2 use the NV3500.

 

Is that all I'll need is the pcm?

 

wiring harness for the engine as well.

 

What do you mean? I haven't looked at this truck, but other vehicles I'm familiar with have wiring under the hood that plugs into a large firewall socket then all the wiring is inside the vehicle. Is what you're talking about different. Or do I need all the wiring under the hood on the V8 vehicle?

 

Need the engine harness for the replacement motor. More cylinders. It's port fuel injection, so, there are going to be two more injectors to deal with. I do believe you can just ADD the wires to the current harness, and use the correct PCM for the motor/trans combo, (may need to extend wires from some sensors as well....) or, get your current PCM flashed for the correct combo, and be good to go on that aspect of it. Don't know just how 'modular' the harnesses are on these trucks. Haven't had to delve to deeply into that myself.

 

I don't know what you meant by " Modular the harness on these trucks are". I understood the rest though.

 

On some vehicles, you can pull the motor without having to disconnect EVERYTHING electrical on the engine, there is one plug, and it all comes out with the motor. Modular. I don't think dodge did that trick.

 

You may have an AX15 transmission, that's what my 98 3.9 has. It will still bolt to the 5.2 since they share the same bolt pattern, but I am not sure what flywheel/clutch setup to use, I am planning on doing the same swap.

 

97-99 by dakotas will have an ax-15 manual trans.

it will bolt up to the 318. Hell itll even bolt up to the hemi.

You will need a new engine harness for a.manual trans v8 truck, but the pcm can be tuned to run a v8. Hit up flyin Ryan performance for tuning.

my Dakota is a 98, was a v6, now a highly modified 360. Has the ax-15.