pi spec cams in npi heads

96SCstang

New Member
Jul 22, 2006
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novi, MI
ok...you can see my mods in my sig and i am going to be adding a fmic this winter as well as a TON of suspension and brake mods. my question is can i run a stage 1 blower cam on the stock npi heads without any problems? :shrug: i know there is a lift difference of .050 but is that really a problem? plz dont tell me to put pi heads on or anything like that. i am not looking to do that. i already make good power and dont want much more but would like to put a little more aggresive cam in if possible. any suggestions on a cam would be great!!! thanks guys. :flag:
 
The NPI grind is gonna be more safe. The problem is the valve spring installed height is shorter on the NPI head, thus allowing for less lift on the cams. The valve springs will go into coil bind around .540-.545". The Crower offset retainers help alot, but even then the max lift their engineers decided to run is a .532". Now, if you took the heads off, and had the spring seat machined a little, you can run a slightly larger lift, but still not as aggresive as the PI stage 2 cam which can be .570"+.

Hope this clarifies, and let us know if we can make you a good deal on some cams, and springs.
 
The NPI grind is gonna be more safe. The problem is the valve spring installed height is shorter on the NPI head, thus allowing for less lift on the cams. The valve springs will go into coil bind around .540-.545". The Crower offset retainers help alot, but even then the max lift their engineers decided to run is a .532". Now, if you took the heads off, and had the spring seat machined a little, you can run a slightly larger lift, but still not as aggresive as the PI stage 2 cam which can be .570"+.

Hope this clarifies, and let us know if we can make you a good deal on some cams, and springs.
I agree with Emerson here, NPI heads wer're designed for .540-.550 lift like a lot of PI cams like to use. Although a NPI blower cam would be hard to find. A custom ground cam sounds like what you need.