Cams+NPI Heads?

SRT Handz · Mar 25, 2009

What cams will work with NPI heads and NPI Pistons?

Can we get a list Going?

Discuss.....

Petek · Mar 25, 2009

'crower, and comp cams produce npi cams, im sure there are more too. anything at or under .500" / .500" lift should be okay.

glittle75 · Mar 25, 2009

pretty much anything without .550 lift and lots of duration. theres really no difference in cams for NPI and PI, PTV contact happens on the edge or "lip" on the outside of the piston, the dish has nothing to do with it.

pretty much any cam made for a 2v will work as long as you degree it in.

fastgtfairlane · Mar 25, 2009

why would you even consider cams on stock npi heads any way. thats a total waste of money and work

GaryG · Mar 25, 2009

fastgtfairlane said:
why would you even consider cams on stock npi heads any way. thats a total waste of money and work

maybe he wants to be different from every other mustang person

Magic · Mar 25, 2009

Even a set of PI cams are a worthwhile upgrade for Non PI heads.

Petek · Mar 25, 2009

glittle75 said:
pretty much anything without .550 lift and lots of duration. theres really no difference in cams for NPI and PI, PTV contact happens on the edge or "lip" on the outside of the piston, the dish has nothing to do with it.

pretty much any cam made for a 2v will work as long as you degree it in.

stock NPI heads cant support hi lift cams, thats why NPI cams usually spec out at .500 .500 lift, and usually have lots of duration, nothing to do with PTV clearance. and all cams should be degreed properly imo.

blown98gt · Mar 26, 2009

MPH custom grind cams lol

SRT Handz · Mar 26, 2009

VT Stage 1 cams have too much lift for NPI Heads huh?

GDTrumbo · Mar 26, 2009

To go over .500" lift, your gonna have to go to the PI head. If your already got it torn down that far and are most likely gonna "degree" the cams anyway, might as well do the heads, timing chains, rubbing blocks and tentioners while your there. On mine, I'm just gonna drop a complete '04
crate engine and new clutch/pressure plate assy. into it.

GT

1996mustangGT · Mar 27, 2009

SRT Handz said:
VT Stage 1 cams have too much lift for NPI Heads huh?

Handz...
For the Cushman Motorsports (Formally VT) Stage 1's You will need to get .060" Offset Retainers.
Jim at CMS is AWESOME for camshafts. He sells the retainers as well as the cams.
Expect anywhere from like 25RWHP or more from the stage 1's. Thats straight from Jim...not BS.

And to this guy:

fastgtfairlane said:
why would you even consider cams on stock npi heads any way. thats a total waste of money and work

You obviously have no clue what the potential of the NPI's are, as a pair of ported NPI's are great heads...
and since 90% of us are never going to even break 400/500HP the NPI's work fine.

DropTopPony · Mar 27, 2009

1996mustangGT said:
SRT Handz said:

VT Stage 1 cams have too much lift for NPI Heads huh?

Click to expand...

Handz...
For the Cushman Motorsports (Formally VT) Stage 1's You will need to get .060" Offset Retainers.
Jim at CMS is AWESOME for camshafts. He sells the retainers as well as the cams.
Expect anywhere from like 25RWHP or more from the stage 1's. Thats straight from Jim...not BS.

And to this guy:

fastgtfairlane said:

why would you even consider cams on stock npi heads any way. thats a total waste of money and work

Click to expand...

You obviously have no clue what the potential of the NPI's are, as a pair of ported NPI's are great heads...
and since 90% of us are never going to even break 400/500HP the NPI's work fine.

Winner winner chicken dinner....
You can run the Crower offset retainers or have your spring perches machined. Then you can run PI spec cams in your NPI heads or just get a set of NPI specific cams.

1996mustangGT · Mar 27, 2009

YES! I WAS RIGHT FOR ONCE!

fastgtfairlane · Mar 28, 2009

i can see the use of an aftermarket cam for a set of PORTED npi heads but thats not what is being dicussed. i probably know about as much as you do about the 4.6 and which is why i dont care to own one

97stanger · Mar 28, 2009

I run stock PI cams with my non pi head/piston setup and dont like them at all. It may be because i need a cam with more duration with my blower setup, but my next mod will be Crower stage II blower cams with upgraded springs/retainers

9psi 98 · Mar 29, 2009

blown97stanger said:
I run stock PI cams with my non pi head/piston setup and dont like them at all. It may be because i need a cam with more duration with my blower setup, but my next mod will be Crower stage II blower cams with upgraded springs/retainers

Which you will totally be able to do. The PI cams I had were not supercharger friendly at all. The duration isn't long enough on the exhaust side so you are losing some of your boost out of the exhaust before it gets a chance to close. Sorry that I took so long to find this thread. You can use an aftermarket cam that has over .500 lift in an NPI head without machining contrary to what a few people might tell you on here. In an NPI head, PTV contact isn't the major issue when installing a cam. The problem is that the valve springs have less room to compress in an NPI head than they do in a PI head. "Coil stack" is not something you want and with a higher lift cam, you are approaching it's limits. I did a lot of research and finally ended up taking my cam covers off and felt around with a feeler gauge just to find out how much space there was in between the coils. A stock PI cam has a .530 lift and that is what I originally had in my NPI heads without any problems. So how can there be a limit at .500 for an NPI head? I currently have CMS Stage 2.5 Blower cams that have are .536/.540 lift, 228/235 .050 duration, 114 LSA installed in my ported NPI heads. Yes, an NPI head can handle a .540 lift and still have some room left....not much though. I used Crower .060 offset retainers just to add a little insurance, but I am 100% sure that I could have gotten away without them.
As for degreeing a cam, some people say it's a must and some others don't even bother. The undisputable truth is that the cam has a keyway on it and can only go on one way. As long as you don't let your timing chains jump the gears to throw your timing off, than you are 99% degreed already. Sure, you can get the timing wheels, tear off the front of your engine and do it the "right way" as most everyone puts it, but if there are no machining issues with your cams (usually if you get them from a reputable company there won't be any issues) they are doing exactly what they are supposed to be doing because of the keyway and the already correct timing. Degree them if you want, but I think it's a waste of time if you did a good install and kept things lined up the way they should be. It's always smart to turn your motor over by hand just to make sure everything is not going to collide inside the cylinder anyway.

1996mustangGT · Mar 29, 2009

fastgtfairlane said:
i can see the use of an aftermarket cam for a set of PORTED npi heads but thats not what is being dicussed. i probably know about as much as you do about the 4.6 and which is why i dont care to own one

I wasn't trying to offend or say I'm more knowledgeable than you

I apologize if I came off that way..

9psi 98 said:
blown97stanger said:

I run stock PI cams with my non pi head/piston setup and dont like them at all. It may be because i need a cam with more duration with my blower setup, but my next mod will be Crower stage II blower cams with upgraded springs/retainers

Click to expand...

Which you will totally be able to do. The PI cams I had were not supercharger friendly at all. The duration isn't long enough on the exhaust side so you are losing some of your boost out of the exhaust before it gets a chance to close. Sorry that I took so long to find this thread. You can use an aftermarket cam that has over .500 lift in an NPI head without machining contrary to what a few people might tell you on here. In an NPI head, PTV contact isn't the major issue when installing a cam. The problem is that the valve springs have less room to compress in an NPI head than they do in a PI head. "Coil stack" is not something you want and with a higher lift cam, you are approaching it's limits. I did a lot of research and finally ended up taking my cam covers off and felt around with a feeler gauge just to find out how much space there was in between the coils. A stock PI cam has a .530 lift and that is what I originally had in my NPI heads without any problems. So how can there be a limit at .500 for an NPI head? I currently have CMS Stage 2.5 Blower cams that have are .536/.540 lift, 228/235 .050 duration, 114 LSA installed in my ported NPI heads. Yes, an NPI head can handle a .540 lift and still have some room left....not much though. I used Crower .060 offset retainers just to add a little insurance, but I am 100% sure that I could have gotten away without them.
As for degreeing a cam, some people say it's a must and some others don't even bother. The undisputable truth is that the cam has a keyway on it and can only go on one way. As long as you don't let your timing chains jump the gears to throw your timing off, than you are 99% degreed already. Sure, you can get the timing wheels, tear off the front of your engine and do it the "right way" as most everyone puts it, but if there are no machining issues with your cams (usually if you get them from a reputable company there won't be any issues) they are doing exactly what they are supposed to be doing because of the keyway and the already correct timing. Degree them if you want, but I think it's a waste of time if you did a good install and kept things lined up the way they should be. It's always smart to turn your motor over by hand just to make sure everything is not going to collide inside the cylinder anyway.

Did you notice much gain with the cams?? I'm still thinking about grabbing RICK FOCKS SVO charger, so I would be interested to know the gains you got with the cams