[WANTED] Big block factory HP cam
- Thread starter Ori
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fratzog lover
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Rob, what was duration at .050? I know mopar didnt publish them, I read somewhere stock magnum cams were 208/221. Is the summit cam that generous on duration? I know the ramps are smoother.
Those figures are listed in the link as 228 and 241.
That said, I have never seen duration figures come up right on the wheel with a Mopar cam. I think Chrysler did that on purpose.
I think their attitude was, since they had all of their different engine recipes for each bracket of racing, "Just pick out the right cam for your bracket and shut the hell up"
As archaic as some may think they were, those recipes are still very useful today and still work. It removes stupid stuff like "how will the cam sound?" and such like that.
In the end, it really doesn't matter what the specs are as long as the cams do what is advertised. They did then and they still do.
Think of it this way. If somebody had an HP 440 or 383 HP they both used the same cam. What difference does it really make how big the bumps are? For bench racin?
I tend to have Chrysler's same attitude. Pick the one you want, put it in and shut the hell up. LOL
IMO, that could be said of any camshaft as long as the description of operation matched the intended use. I remember a time when there were no specs given other than "stage 1, stage 2" and so on. They all performed as advertised.
One more note of interesting detail. Mopar Performance also started the shortcut reference to their camshafts by lift. For instance "The 557 cam" and so on.
I also think the .850 guidline for checking .050 duration was a scam to keep people in the dark as to their proprietary information regarding how they measured and ground cams.
They do not work out either way. Using .750 like every other conventional cam or using .850. The math does not come up. They had to know this. I firmly believe there IS a formula for figuring the Mopar cams out on paper. No way could they have not known the math did not come up right. That's why I believe it was intentional.
Also to worthy of note. All through the Mopar engine book, it is always said not to use duration @ .050 as a guide, but to use advertised duration.
When they said this, I believe they were strictly referring to comparisons between Mopar cams. It makes more sense when thinking of it that way.
I also think the .850 guidline for checking .050 duration was a scam to keep people in the dark as to their proprietary information regarding how they measured and ground cams.
They do not work out either way. Using .750 like every other conventional cam or using .850. The math does not come up. They had to know this. I firmly believe there IS a formula for figuring the Mopar cams out on paper. No way could they have not known the math did not come up right. That's why I believe it was intentional.
Also to worthy of note. All through the Mopar engine book, it is always said not to use duration @ .050 as a guide, but to use advertised duration.
When they said this, I believe they were strictly referring to comparisons between Mopar cams. It makes more sense when thinking of it that way.
Good points. A member ( Skrews..) ran the degree wheel on a Purple shaft (528 solid. IIRC...). It came up about 6-8 degrees shorter at.050"( Compared to D.C specs.). Did, what he wanted.
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