PI Heads - What to look for

delling3

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I haven't given up on my plan to do a cam and intake swap on my NPI motor, but my recent issue with a broken bolt in the head makes it more likely that I will have to pull at least one head. If I have to pull the head anyway, it makes the full PI swap more attractive. I have been looking online for a set of heads, and obviously a lot of Fords used the 4.6L 2V motor. Mustang, Crown Vic, Lincoln, F-150, vans, etc. And of course, they all "fit", but are there any differences that I need to be wary of? Camshaft differences between models? What should I look for, what to steer away from?
 

07GtS197

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If you can, try to get heads from an 04+ 2v. That’s when Ford started using the 8 thread heads. Also there will be a provision for a cylinder head temperature sensor, our cars don’t use them but others did.

Also, Blak tested out quite a few 2v cams and if you want the most out of it, stick with pi cams from a mustang as they have the most aggressive profile.


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PinkieT

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If you can, try to get heads from an 04+ 2v. That’s when Ford started using the 8 thread heads. Also there will be a provision for a cylinder head temperature sensor, our cars don’t use them but others did.

Also, Blak tested out quite a few 2v cams and if you want the most out of it, stick with pi cams from a mustang as they have the most aggressive profile.


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I have a set of brand new or newly rebuilt heads. How can I tell if the cams are Mustang cams or not?
 

07GtS197

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There should be an engineering number between the cam lobes if I’m not mistaken.


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apsmith49921

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This may help a touch. But yeah all of the cams should have a number. If its not one of these pull the number and run a quick Google
99a82f80ea66d90269673784be39beef.jpg


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apsmith49921

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I haven't given up on my plan to do a cam and intake swap on my NPI motor, but my recent issue with a broken bolt in the head makes it more likely that I will have to pull at least one head. If I have to pull the head anyway, it makes the full PI swap more attractive. I have been looking online for a set of heads, and obviously a lot of Fords used the 4.6L 2V motor. Mustang, Crown Vic, Lincoln, F-150, vans, etc. And of course, they all "fit", but are there any differences that I need to be wary of? Camshaft differences between models? What should I look for, what to steer away from?
You've got your cams already correct. I'm not aware of any differences in the actual heads between the crown vic mustang etc.

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96blak54

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I haven't found much differences in model years within the pi heads. Some engineering changes, add ons improvements are about it. The lack of available parts to dissect restricts the knowledge. However that could change here soon.

Pi heads on top of a npi short block is the classic hp improvement. Many have done it with great success.

A full pi swap has a marginal hp increase. Not to say its a bad thing to swap one in, but it wont be the camaro killer.
 

delling3

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You've got your cams already correct. I'm not aware of any differences in the actual heads between the crown vic mustang etc.

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Well, I have a set of Bullet Cams that are a custom grind for NPI heads. I don't think that they can be run in a PI head, so if I opt for the full swap, I will need cams, and will have a set of NPI cams that maybe someone else can benefit from.
 

96blak54

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Wait....bullet cams for npi heads? If the cams can run in npi heads, they can also be ran in pi heads no problem. Its the npi heads that have a lift limit. IIRC max comfortable lift for npi heads are roughly .530" while pi heads can go close to .600"..... Im a little bit rusty with the technical lift values of each, but the pi heads can take more.
 

96blak54

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The reason why pi heads are so grand over the npi, is mustang camshaft profile, exhaust lift values, heavy valve and reduced spring pressure rate. These attributes with rpm causes the valves to delay closing better known as valve float.
 

joe65

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i might have a set of pi heads in the coming months from my 00gt. i also have a set in the garage that are ported with new valves and springs and valve job.
 

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