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Also, everyone tells me wilder cams are less wild in bigger engines. I mean, what is your definition of gas guzzling?
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I'm not sure that I agree with conventional wisdom on this one. As far as I can tell, a wild cam is a wild cam (unless the porting isn't opened to match in which case moving a given cam to a larger motor will make the cam act milder. But that's a function of the porting, not the capacity or the cam). A case in point is the 906 cam which was used in the 2.0 906, 2.3 and 2.4 911ST and the 2.8 and 3.0 RSR's. The peak HP came at about the same point in each engine: 8000 RPM while the peak torque was also at the same point in each engine: 6500+/- RPM. The engine size grew by 50% but the "wildness" of the cam didn't seem to change.
I doubt that lots of overlap (ie: a "wild" cam) has lots to do with decent MPG. Why? Engine's develop their best milage just below or around their torque peak. It also helps that in general street engines (especially those with Webers) are running "choked" on the idle circuit using low RPM's. Race cam's on the other hand give away low RPM performance because of their overlap in order to get the ram affect at higher RPM's. Using a high CR helps to offset this somewhat, but at low RPM's engines with race cam's are not running that well. As a result they don't get very good combustion and a lot of unburnt fuel is going out the exhaust pipes. This is why a sniffer will flunk an engine with a race cam in notime - it will fail at least the Hydrocarbon test. And when that much fuel is going out the exhaust, you are not getting good HP.
If you want decent milage and a street engine, then you should be running something like a Solex or E cam with fairly high compression. Your milage will go up further if you use a T cam with it is optomised for the rev range where the engine will develop the best HP. If you want a lot of HP out of a given engine size, you'll need to spin the engine faster. To do that you'll need a "wilder" cam. Unfortunately you'll need to pick which is most important, or how much of a compromise you want to live with.
The only other option would be to come up with a way to retrofit Porsche's "Verioram" and variable cam timing onto your engine. THAT will provide great HP and milage all in the same package.