Anyone know what exactly i need to swap a 5.9 v8 In to a 2001 3.9 v6 Dodge Ram 1500 single cab ? All I have so far is a 5.9 v8 out of a 1998 Dodge Ram

 

Wiring harness, or, simply add the additional needed wires to your current harness. (two injectors) Reprogram the PCM to run the V-8. May need to extend some of the connectors if you use your existing harness for the sensors on the front of the motor. (temp, etc.) Aside from that, there are likely some other little things you will need, but, it's a pretty straightforward swap.

 

Auto or manual?

 

It’s an auto can I used a 5.2 harness or does it need to be a 5.9 harness

 

You will have to use the 5.9 flexplate and torque converter, along with the transmission. The 42RE that comes behind the v6 won't hold up well behind the 5.9, a 46RE is what the 5.9 uses.

 

Either V-8 harness will work.