472 cam selection

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http://users.elknet.net/mts/page29.html

i was wondering on this site, what is the most aggresive cam i can get with stock valve train, heads, and stock pistons. i am worried about piston clearence. i would like the 15 series cam, but have heard that with stock engine, its not recommended to go over .5 lift. thanks

[Al from MTS]

Using a performance cam in a stock Cad engine raises some issues.

1. Maximum lift you can use untill you will cause the spring retainer/oil seal to hit the top of the valve guide.
2. Stock valve spring pressures and coil bind
3. Compensating for reduced cam base circle which lowers lifter in engine.

MTS EZ install cam kits are designed for use in stock Cad engines. Our #VT10AR cam is what I feel is the most you can use in an engine with stock valve springs. The EZ kit uses special retainers and oil seals to allow for higher valve lift without machine work to the heads.
Main reason I say the #10 grind is max to use is stock valve spring pressure. We could grind a hotter cam. Problem is the stock valve springs would float long before you could use the hotter cams full potential.
Longer push rods or shortening your stock rocker T pedestals will take care of the reduced base circle.
A scary as the stock rockers may look, they will work fine if they are not all worn out.

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if i wanted to use the 15 grind cam, what is the list of parts i would need to replace?

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would i need to replace more than the vavletrain?

[Big-Daddy]

Al-
Your answer confuses me a little.

You say a #10 grind is the max advisable for a stock valvetrain...

And then you say the EZ install kit allows you to use a hotter cam, but you dont diferentiate between the EZ kit and the #10 cam.

Now I understand that a "hotter" cam is useless with a "stock valvetrain" due to valve float, but to install the EZ kit, dont you have to [at least partially] tear the valvetrain apart??? Would it not make sense to replace the stock springs with some stiffer ones at that time???

Why in the world would anyone install the special retainers from the EZ kit on crappy stock springs????

So I guess the question I need clarification on is this,

If I [or someone] was to install the EZ kit along with some stiffer valve springs, would it then be possible to use a #15 grind cam???

At what point [a number please] do you absolutely need to have the valve guides machined down to use a larger cam???

How much lift can a 100% stock valvetrain take? How much more with the EZ kit? And where will I run into trouble first? Coli bind? Guide to retainer?

Thanks Al, you 'da man!

[Al from MTS]

EZ cam kits are designed for "junkyard blaster" engines. The main reason to run a #10 EZ cam is three words. Money, Money, Money.
I put these kits together cause folks have asked for years. The #5 version works great. It's just an updated version of a stock 1973 cam. Stock springs are not over taxed.
The #10 grind is a push. The #10EZ cam is cut with slower lobes than our MT series cams. The special retainer and seal trick cures the machine work deal. It will out run a #5EZ cam equipped engine. It won't run as hard as an MT10 cam with our aftermarket springs.
So if you are on a tight budget, the EZ kits will add power and save cash. In my opinion at the #10 level you are better off going with our spring package if the budget will allow. If not, you still can't beat it for the bucks.
I over design our stuff here @ MTS. I like at least .100" clearance to guide @ full lift. That why even our EZ #5 cam has you change oil seals. I plan on guys over reving and abusing stuff. So I keep my tolerances big on what I recommend.
Based on that i wont run over .480" lift on stock heads with stock springs, seals, and retainers.