Jump to content

96-98 Pi swap related questions answered

Recommended Posts

I made this up for another forum im on and figured I would share it here.  These are the typical questions that i tend to see from the sn95 crowd.




What is a PI swap:

Pi or power improved parts were found on 99-04 GT mustangs.  It consisted of different heads, intake, and cams from the 96-98 (NPI) years. 


The Pi swap guide:


This is the most complete guide i have found.  Rather then copy it and take the credit here is the link.


What will a PI swap do for me:

NPI cars typically dyno around 190rwhp stock.  After doing a PI swap gains of 50-60rwhp are common (240-250rwhp).  Yes this is more then a PI mustang stock.  The added HP comes from the bump in compression.


Can I use aftermarket cams with a PI swap:

Yes.  Pretty much all stage 1 cams will fit and most of stage 2s.  PTV problems can occur with some stage 2 cams.  This can be corrected by a couple different ways.  While degreeing the cam if PTV occurs, you can advance or retard the cam.  

Before the heads are assembled, you an take them to a machine shop and have the valves milled for added clearance.  MHS also sells valves already machined for extra clearance.  


Do I need a tune:

A tune is not required, but as always to get the most out of your mods its a good idea.  


Which grade fuel should I run:

With a full Pi swap you should run 93 octane if available.  Most people experience pinging when running lower grades of fuel.


What is a PI half swap:

A PI half swap consist of swapping a PI intake and PI cams onto your NPI motor.  


What is the benefit of a half swap:

Since swapping heads out are intimidating for a lot of people, this is something that can be done without much knowledge of motors. A big restriction with our cars is the intake.  From the intake swap alone you can see gains of 15rwhp.  This is a fairly straight forward swap.  Adding pi cams is a little more tricky but still fairly straight forward.  PI cam swap will help add another 10-15rwhp.  The easiest time to do this is when the intake is already off for the Intake swap.


Pi intake swap guide(thanks to MHS):



Cam swap:



Cam Degreeing:



Can i swap a pi engine into my car:

Yes this is about as straight forward of an engine swap thats possible.


What other vehicles have PI parts:

Crown vic's, Explorers, F150s, Expeditions.  (Note: The trucks and suv's run different intakes more suited for their needs)


Can i use Windsor heads on my Romeo block:

Yes.  Some minor things will have to be changed. You will need a windsor timing cover, and valve covers.  These will also require a few extra bolts over the romeo's.


How to tell if my heads are Romeo or Windsor's:

The easiest way is to count the valve cover bolts.  Romeos have 11 bolts, Windsors have 13/14.  The Windsors have a pressed on cam gear while the Romeo is a bolt on.


Will my stock exhaust manifolds work on the PI heads:

Yes there is no difference, but now would be a good time to upgrade them.


Boost and my Pi swapped motor:

Can you add Forced induction with a pi swap?  In short answer yes.  Compression is not bad for boost, the most concern comes from the mileage on these cars.  Since these cars have been around for over 15 years, chances are they have some miles.  With the added compression and then adding boost it is typically a recipe for disaster.  The general rule is the bottom end (stock) can handle 400-450rwhp with a good tune.  


Will a 4v fit in my car:

Yes.  This has been done many times and has a lot of potential.




Link to comment
Share on other sites

and if anyone would like firsthand experience with a PI intake install onto NPI heads, here is my writeup with my experience.



Link to comment
Share on other sites

Thanks, this is stuff i have found while researching for my car.  A lot of this tends to get asked a lot, and i couldnt sleep last night so i decided to do something useful with my time haha.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

SN95 Source ©

The premier SN95 Community

  • Create New...