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Reply to "Questions regarding George's 275/285 Custom Street Cam Profile"

Again, not the real George here...but it seems nobody else wants or can answer. so I try it.

My theoretical thoughts of your cam:

As a rule of thumb a single pattern cam like yours (intake duration = exhaust duration) is optimal for a head that does not differ more than 80-80% between intake and exhaust flow. (I have never seen flow numbers of OEM heads, that are at 85%, so I absolutely can't understand why e. g. compcams produces so many single pattern cams for all types of engines)

Because the original 4V heads are a perfect example of flow difference between intake and exhaust

(Chart by the real George ) https://pantera.infopop.cc/top...975#1598208419816975

At 0.500 lift for example the exhaust port flows less than 70% of the intake port.

That is why GeorgeP chooses these lobes with such big difference between intake and exhaust, to help the exhaust port.

In addition you have a tight LSA of 110°, this will cause reversion into the intake at low rpms.



If I would have to guess:



You will have a narrow rpm-band where your engine has "steam", how narrow depends on the rest of your engine. This doesn*t mean, that your car will be undriveable.

What GeorgeP tries to achieve is a broad torque curve like a stock cam but using modern lobes and more duration, but NOT using a tighter LSA. Perhaps you can look at it as stock+1.

If your car runs with that cam, please tell how it feels, and in what rpm band it drives best.

Edit:

After rereading my own post, I felt the need to add: "Sorry for my bad english!"

Last edited by GeorgS
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