non pi head/pi cam and pi intake hp gains

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So to answer the question, a stock PI H/C/I swap is worth 45 hp on a good day, vs just the intake and cams at 25-30. So you are looking at 15ish hp more with the heads. But, that extra increase in compression hinders you in the future if you are going boosted unless you have a built motor. Back in the day, I was thinking about going with the PI heads, but decided against it on account of the possibility of going blown in the future. Glad I made that decision. :D

I think this is about right. I don't know my stock numbers but with the listed mods I had about 250/295 numbers.
 
If you are going forced induction then a full head swap would be give you too much compression on a NPI motor.

As a side note if you look at my numbers they are a little low. I've been told I have more potential in my tune....just haven't followed up on it. Basically I'm at a N/A stock 99+ GT crank rated HP. I could realize another 10-15.
 
If you are going forced induction then a full head swap would be give you too much compression on a NPI motor.

As a side note if you look at my numbers they are a little low. I've been told I have more potential in my tune....just haven't followed up on it. Basically I'm at a N/A stock 99+ GT crank rated HP. I could realize another 10-15.

lol I was kinda confused after looking at your numbers, but then I remembered the '96 and '97 models 4.6's had lower numbers than my '98, from stock arent we rated at TQ-295
 
so if you do just a pi intake swap no cams, on a non pi heads would it hurt the motor. what o you think the hp results would be. and what do you think about this intake set up?
 
so if you do just a pi intake swap no cams, on a non pi heads would it hurt the motor. what o you think the hp results would be. and what do you think about this intake set up?

I wouldn't hurt the motor at all. Generally you can expect 10-15 hp with the PI intake, especially at the top of the RPM range. The NPI really loses its breath at around 5000 rpm while the PI intake continues pulling and levels off around 5500-6000 rpms.

There is also no need for the intake spacer/adapter kit. If you use PI gaskets with the install, you just need to put a little RTV in the coolant ports because they won't seal properly with the PI gaskets.

Here's a really good article on the PI intake and cam swap. If you're just doing the intake, disregard the cam stuff.

NPI to PI Cam/Manifold Swap HOW TO - Mustang Forums at StangNet
 
I did the NPI to PI swap but I had some homemade adapters that a guy had for sale a while back. If I remember correctly I gained 4 tenths of a second at the track untuned with just the intake swap. Not sure what the translates into HP but I was happy with the gains.