What's the Best N/A Cam?

Discussion in 'SN95 4.6L Mustang Tech' started by fshawn50, Aug 28, 2009.

  1. I called modular head shop today and asked about cams and heads. and they told me they had some monster cams coming out for the npi head. should make a lot of power on a stock npi head with a pi intake. he said they are going to have dyno #s pretty soon. I can't wait to see what it makes. ill be sold if it has a good curve and makes power..
  2. ill have to keep my eye on them, my goal is to come close to 350rwhp N/A NPI, so maybe these will help, hoping to gain the 35+rwhp with the edelbrock intake, electric water pump, and different cams!
  3. that would be sick!!!
  4. x2

    I like all the info MHS has put out too. I'll have to talk to them about a good PI swap cam.
  5. NPI heads have one amazing lustful gargantuan advantage over PI heads - they have 0.1" more intake valve to piston clearance - and knowing what I now know there has never been an off the shelf "street/strip" cam that took advantage of this.

    Some newly released NPI NA cam specs (new custom lobes are being made as we speak):

    Bullet Stage 1 NPI
    220/223 duration at 050
    525/500 lift
    106/112 centerlines
    109 LSA

    Bullet Stage 2 NPI
    225/228 duration at 050
    525/500 lift
    106/112 centerlines

    Funny thing, the SMALLER of these 2 cam specs will bend the valves in a stock PI motor. The bigger cam will need both aftermarket valves and piston notches in a PI motor unless you like 0.005" of running clearance.
  6. what kind of power band do you think these cams will have?

  7. Those designs are being targeted to boost the midrange as much as possible, peak HP somewhere around 5200-5500RPM for 6000 or so shifts. I would think the torque curve will be pretty serious, that is what the install centerlines are set up for. I don't know how quick the power will drop above 6000RPM, that is the wild card at the moment. I know they should carry pretty flat to 6000 as I already tested a 220/218 108/108 version with a stock PI motor and it was good to 6000, above 6000 it dropped like a stone.
  8. This is some exciting news for us NPI guys. Keep us updated.

  9. Other new NPI specs. To run 550 lift you need to run Crower +0.060 retainers and the TFS springs with 0.030" shim makes the best combo IMHO for the NPI head. These cams should get a different intake manifold IMHO. You will need piston notches for sure at the 3 and 3.5 level and probably for the 2.5 as well.

    Bullet Stage 2.5 NPI
    228/230 duration at 050
    550/525 lift
    106/112 centerlines

    Bullet Stage 3 NPI
    233/235 duration at 050
    550/525 lift
    106/112 centerlines

    Bullet Stage 3.5 NPI
    238/240 duration at 050
    550/525 lift
    106/112 centerlines

    I have a set of the 3.5 here along with a Logan intake to try out on some NPI heads :D

    Bullet also is releasing 5 updated all new NA cam specs for the 4.6 PI motor, 5 new NA specs for the 5.4 2V, and 5 brand new NA specs for TFS head motors. Main change on the 4.6 PI cams is the exhaust is now smaller than the intake lobe on all cams and the LSA is tighter. The 5.4 PI cams are like the 4.6 cams but they are advanced much more since there is not as much piston to valve problem so now they are unique and specific as well. Before the NA cams were made to kind of cover the NPI, PI, and 5.4, but in reality they all need something different for each to be optimum so now its getting done.
  10. Any dyno #'s for these yet? I'm guessing one of these would be a good cam for a DD PI swap car? Or would one of the NPI cams be a good fit?

    BTW thanks for all of the good info. Your hard work is greatly appreciated.
  11. PI Heads = PI Spec'd cam.

  12. No dyno numbers on the NPI cams, I bought a near mint stock 96GT that we are going to use for testing the smaller cams and my current GT is getting a NPI head/Logan intake motor for testing the bigger ones. All this testing is still a couple months out at a minimum.

    These NPI spec cams will bend the valves instantaneously in a 4.6 with PI heads be it stock or swapped. This is no joke, they will not work in a PI head 4.6 motor unless you have piston notches.

    Bullet has 2 new Stage 2 4.6 PI cams:

    Bullet Stage 2 4.6 PI
    225/223 duration at 050
    550/500 lift
    110/110 centerlines

    Bullet Stage 2P 4.6 PI
    225/223 duration at 050
    550/500 lift
    108/110 centerlines

    The P version is for ported heads or stock heads with modified intake valves. The only difference compared to the regular Stage 2 is the intake valve is advanced 2 degrees to a 108 centerline which is a good boost to the midrange with no loss of top end. To do this you need another 0.030-0.040" of piston to valve clearance over a stock head. The P version in a stock 4.6 motor will have about 0.005" of valve to piston clearance. Though many people are running cams with intake specs identical to these with stock heads I can't recommend it after measuring it myself. Modifying the intake valve or replacing it with an aftermarket one gives the needed safe clearance. First set of these cams is going to Indiana for a motor build.

    Anything bigger than this you have to notch the pistons with a 4.6 PI.
  13. This is one of the best threads I've seen in the 4.6 section of StangNet. Thank you for bringing factual, very useful information here.

    Think I'll mark this thread for future reference (hopefully).

  14. Here is a dyno run of a NPI cam between the Stage 1 and Stage 2 specs:


    Car was a Mustang with a stock NPI motor with PI intake, offroad X, shorty headers, loudmouth catback, C&L plenum, and CAI.

    He has another dyno run from another location that showed 265RWHP on a canned tune in 96F temperature so it kinda confirms the 273RWHP run.

    Cam specs were:

    222/226 duration at 050
    525/500 lift
    108/114 centerlines
  15. Was this on a Mustang dyno? If so, :jaw: Those are some awesome numbers! I might have to keep my eye on this if I ever decide to swap out my cams.

  16. wow thats awesome
  17. so quick question for everyone, will the brand X best N/A cam for the PI heads still be the best for the trickflow heads since they are a different design? Im getting a set of trickflow heads and i want the best N/a cam for that setup. Anyone know if it will be the same or no?

  18. Nope, the flow bias is different, the intake centerline needs to be earlier, and the stock plastic intake maxs out really fast so if you overcam it you lose a ton of power.
  19. well does anyone know of a good cam for the trickflow heads? im looking for around 350rwhp and i think the trickflow intake will be good but im keeping my options open.

  20. Currently working on it, I am flow testing a TFS head with a plastic intake mounted shortly to see just how bad it kills the flow.