nickmckinney

Rather than take only my word for it here are threads with other people's findings as well:

http://www.modularfords.com/forums/s...d.php?t=148107

http://www.stangnet.com/mustang-foru...est-n-cam.html

http://www.modularrevolution.com/for...ad.php?t=13103


I have owned VT Stage 2 cams myself, and used/tested just about every other NA cam on the market now. Get a stock motor, use the instructions on my cam degree and PTV clearance page, and confirm it for yourself as others have done as shown by these threads.

Trust me if I could fit a 225 intake duration at a 108 centerline in a stock head and keep a straight face that it has at least 0.015" of clearance I would not have the MHS Stage 2 spec at a 110 centerline. To be honest I would prefer a 106 centerline as that makes more midrange still without any significant loss of top end power with the plastic intake manifold.

IMHO - the best street performance NA cam with a stock PI head is 220-235 intake duration installed at a 106 intake centerline and a slightly smaller exhaust lobe at a 108-110 centerline but not even the 220 will fit at 106 without a piston notch with the craptastic PI head PTV clearance issue. 220 installed at a 108 gives 0.015" on a stock 4.6 PI (yes I measured it) and 225 installed at a 110 gives 0.035" on a stock 4.6 PI. I REFUSE to allow anyone to run closer and bend a valve and yes I got into this cam market because I paid for bent valves on customer's cars with cams that were supposed to fit that are mentioned in this thread.

nickmckinney

Since the above links didn't transfer properly let me try it again:

http://www.modularfords.com/forums/s...d.php?t=148107

http://www.stangnet.com/mustang-foru...est-n-cam.html

http://www.modularrevolution.com/for...ad.php?t=13103

teej281

all three links arent found by my browser...but i hate that you posted the right links before i could submit my post. lol

stangalator

if 220 at 108 gives you .015 what does 225 at 108 give you?

so hitech stage 2's then, very large duration (234), but its at 111.

im leaning towards the mhs ones because they are "safer"

mrtstang

225 at a 108 will be to close with the stock PI intake valve. This is off MHS's site.


46PI STAGE 2P - NATURALLY ASPIRATED 225/223 550/500 108/110 109
Advanced intake lobe version of the Stage 2 cam. This is the cam to use if you are willing to remove the cylinder head and replace the intake valve as it will give more midrange torque than the Stage 2 with no loss of top end power. PTV is very tight with the stock valve and this cam, you only have about 0.005" of clearance with the stock valve and piston with this cam. With the modified intake valve you are safe

nickmckinney

0.005" is what I found with a stock thickness head and stock shortblock with the piston 0.015" in the hole.



Their original spec was at 110 and their new spec is at 112 (intake centerline, not LSA, they retarded the cams 2 degrees somewhere along the way)

At 112 I found 0.005" with a stock thickness head and stock shortblock with the piston 0.015" in the hole with this particular cam. This cam has the same intake lobe as the Comp 270 which Comp had to retard back to 113 intake centerline from the 109 they originally started at.



You can make the other cams "safe" to run by either changing/modifying the intake valve and/or retarding the intake centerline. If the heads are coming off anyway its really easy and cheap to do.

Let me state ALL PI cams intended for stock 4.6 PI motors have compromised specs somewhere. You just have to pick what you can live with. Our Stage 2 and Stage 2P specs are installed at a higher intake centerline than I would prefer actually but to get lower there just isn't enough room. However if you call me after installing a set of cams I speced because you bent your intake valves its because you have an installation error. I have done enough research and test fitting to know I ain't replacing anymore bent valves on my dime.

stangalator

great info here. thanks guys! I would need some adjustable cam gears to adjust center lines and degree any cams, correct?

Keeping this in mind, what cam would you then think is correct for me? My pi heads are port match and the castings are cleaned up on the intake side with a mirror finished exhaust side.

Im leaning towards the mhs stage 2's or maybe mhs stage 2.5's, i dont want bent valves


edit:

mhs 2's
225/223 550/500 110/110
mhs 2.5's
228/226 550/500 110/110

so maybe the 2.5's would be a little better?

lizzyfan

Good stuff Nick!!!
My question to you is: Will the TF heads help with PTV clearance with the relocated valve??

teej281

^^^Good question.


I feel like that soldier in transformers 2 talking to optimus. lol

WannaBeGearHead

Wow it is great having someone chime in that has extensive knowledge and experience about this topic. Great info Nick!