Sixpackstang's Official Split Port Swap Post

metalman302

Active Member
bringing this back since it hasnt been updated in a very long time. ive read countless pages on split port swaps,and have yet to find a step by step guide to doing it,nor are there 100% answers to some of my questions. i have a 1995 mustang,it has an auto trans, i want to put a 1999 complete motor into it( the one in it is blown) my main concerns are the wiring changes and what will i have to do to attach that 99 motor to my 95 auto trans? and depending on who you ask the parts list needed will change every other post, maybe its just me but there doesnt seem to be solid guide on how to do this,not to piss off the op there is alot of good info here,it just seems sloppy.
That's because there are several ways of doing things. Also there are many different combinations of what you are starting with and what you are swapping to.

The 95 and 99 motors use the same balance, bellhousing, and flywheel pattern.
 
Well I'm not entirely sure on that...but look at it this way. How much more hp/tq did the 01+ mustangs have over the 99-00 that have no IMRC's? I think maybe 3/3 or something small like that. Is that worth all the headache to get them to work?
The extra HP isn't why Ford added the IMRC. By closing off the short runner, torque is increased from low to mid RPM range. That makes the car more responsive at part throttle.

I'm planning to swap in a complete '01 engine and 4R70W tranny and use the corresponding harnesses and PCM. If I can retain the return style fuel system that may make it a little easier as I wouldn't need the '99 up fuel pump and associated wiring. I'm still gathering parts for the swap and haven't yet decided how to tackle the fuel system. It looks like everyone else has opted to modify the original harness. I would rather not do that since the 4R70W needs the correct PCM to shift properly and that also seems to be the easiest way to keep the IMRC functional.
 

NMStang218

Hello My Name Is
Not sure if it matters but I'm using a 99+ pump in my 98 and have not experienced any issues. It's been about 5 years now.
 
Not sure if it matters but I'm using a 99+ pump in my 98 and have not experienced any issues. It's been about 5 years now.
Going the other way is where the problem would be (not having a variable pump). The '99 up is designed to be variable, with the PCM controlling the voltage to it. Lower voltage = lower pressure. By not using the '01 up PCM, it's getting full voltage all the time and the return style fuel system is what's regulating the fuel pressure for you.
 

Xfree143

New Member
The extra HP isn't why Ford added the IMRC. By closing off the short runner, torque is increased from low to mid RPM range. That makes the car more responsive at part throttle.

I'm planning to swap in a complete '01 engine and 4R70W tranny and use the corresponding harnesses and PCM. If I can retain the return style fuel system that may make it a little easier as I wouldn't need the '99 up fuel pump and associated wiring. I'm still gathering parts for the swap and haven't yet decided how to tackle the fuel system. It looks like everyone else has opted to modify the original harness. I would rather not do that since the 4R70W needs the correct PCM to shift properly and that also seems to be the easiest way to keep the IMRC functional.
I recently purchased the complete intake and fuel rails from a guy on eBay. He said he took it of a mustang so I am assuming some else did this mod. I separated the upper and lower intakes and found that the short runners were infact blocked off using a spacer plate. Can you tell me a little more info on why this is done and how does it run without doing this block?
 

Markstang

Polishing my banhammer
I recently purchased the complete intake and fuel rails from a guy on eBay. He said he took it of a mustang so I am assuming some else did this mod. I separated the upper and lower intakes and found that the short runners were infact blocked off using a spacer plate. Can you tell me a little more info on why this is done and how does it run without doing this block?
I think we're going to need to see pictures of this.
 

Markstang

Polishing my banhammer
OK that set of intakes came off of a f-150 they must have the short runners blocked on their v6s for torque. That's not like that on the mustangs. You can get rid of that when you put it in the mustang.
 

Xfree143

New Member
The metal spacer is required correct? So I will need to get a standard one. Did you notice the Bosh hardware on the intake?
image.jpg
image.jpg
 

Xfree143

New Member
It's a small 40mm, I looked it up and it showed up on a couple of web sites for propane conversion kits. It's way to small compared to the stock mustang.
 

Markstang

Polishing my banhammer
no spacer is required at all. The upper intake mounts directly to the lower with just a gasket. The Bosch thing.. I think will be left behind as well.
 

Xfree143

New Member
You'll need to rig up some -bracketry for the throttle cable and iac.
I now have the stock intake off. On the stock intake the short tube ports all have a butterfly system just like a carberator. Not having that on this f150 intake is ok?
 

Markstang

Polishing my banhammer
I now have the stock intake off. On the stock intake the short tube ports all have a butterfly system just like a carberator. Not having that on this f150 intake is ok?
Hold on, you have a splitport motor already? What exactly are you trying to do?
 

Markstang

Polishing my banhammer
looked at your profile and garage, you have a 2003, why did you buy an upper and a lower intake? Your motor is already splitport, so the most you can do with what you bought is put the upper on your current motor if you put the lower without the butterflies on the motor you have now, you'd need to have it tuned to delete the IMRC functions and have the fuel tables fixed.
 

Xfree143

New Member
looked at your profile and garage, you have a 2003, why did you buy an upper and a lower intake? Your motor is already splitport, so the most you can do with what you bought is put the upper on your current motor if you put the lower without the butterflies on the motor you have now, you'd need to have it tuned to delete the IMRC functions and have the fuel tables fixed.
Lower intake came with the upper, fuel rails, plus a few other things at $225. At the time I wasn't aware that I didn't need the lower for the F150 intake. So I will use the stock intake.
I already have a Bama tuner, will I need it adjusted with the new intake? Or am I good just as long as I use the stock lower intake?


Thanks for the help.
 

Xfree143

New Member
Will the f150 fit under the stock hood or is it like the windstar kit sorry to but in
no it will not fit on a stock hood. I'm trying to figure out if I can get a GT aftermarket scoop to see if it will cover the hole I would have to cut.
 

Markstang

Polishing my banhammer
No tune necessary for the stock lower intake. Tune necessary for f150 intake since the Intake Manifold Runner Control valves are gone from it.
 
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