I have a 93 Dakota with a 5.2 ltre in it and I also have a 93 with a 3.9 ltre. I am wanting to put the 5.2 in place of the 3.9 in my good truck. I am going to leave the computer harness hooked to the engine and am swapping the computers also. Will the manifolds on the 5.2 fit the y-pipe from the 3.9, or will I have to change them? I think I am in good shape to do the swap since the trucks are both the same year . I am just hoping that the y-pipes are the same. What do you think?

Will

 

I don't know about the specifics, but I know a lot of people have done 4-banger/V-6 to V-8 swaps. I do know the 3.9/5.2 share about everything in common (but one has 2 less cylinders).
As for the specifics, I don't know.
Here is a write up done for a 3.9 to 360 swap. Yea, I know you said the 318. (Courtousey 360DakotaPwr)
The member OneBadKota also did a swap to a 360 in his Dakota.
You can either do a search here, or go to Yahoo search.
Keep in mind, you will also want to swap the transmissions, since you want the stronger one behind the V-8.

 

Swap should work with a computer change and mount swap. As for the pipe, I am pretty sure they are they same. The A500 transmission will hold the V-8 no problem. But, if you're doing the motor swap.. it's easier just to pull the engine with the transmission and do the swap.

 

Easy swap because they are the same engine just one with 2 less cylanders same bore and stroke and everything it should all hook up just fine