Engine Swap 1996-2004 Need Advice


New Member
Oct 26, 2016
I have a 1996 mustang Gt that has a bad motor in it, I am going to be swapping it out with a low mileage complete engine from a 2004 both being romeo engines, I want to use as many of the new engine parts as possible with that being said what I am i looking at here? is my fuel system and wiring harness gonna plug and play? will i be able to use my original coil pack type ignition to simplify it some? I am pretty good with a wrench but just not sure how compatible this stuff is. Any help would be great
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10 Year Member
Jun 2, 2005
Joplin, Missouri
You will swap your front cover, cam covers, accessories, coil packs, brackets etc onto the new engine. If the engine/intake is not from a car then it may not have the provision for the rear heater core hose and you'll have to fab something up or drill the intake.


SN Certified Technician
Aug 14, 2009
Houston Texas
Put both motors on an engine stand. Make the new one "look" like the old one. Take pictures of every stage of the swap. Re-use the original:
  • motor wiring harness
  • ignition coil packs.
  • fuel induction
  • IAC valve
The goal here is to make the new motor look electrically like the old motor.

There will be some "issues" with:
  • the 2nd temperature sensor. Either use a coolant drain plug or tap the manifold coolant crossover.
  • the oil level sensor in the oil pan. Swap the oil pan to keep the level sensor.
  • the PCV line size. The newer motor will have larger PCV lines.
  • the heater return line through the engine valley. If this were my project I would get a heater return line from a 2001 GT and mate it to the flexible line from the firewall.
However, all of the issues can be over come without a lot of fan fair. Don't over think this. This is a "do'able" swap.
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