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A camshaft fine tunes an engine to produce a torque curve that you are looking for. Duration measured at .050" lift determines roughly what rpm range the engine will be best suited to. 220degrees@.050" makes a good camshaft for economy with some power in a range of 1500-4500, 240@.050" gives up some economy & manners for stronger power in the 2500-5500 range, 260@.050" is getting pretty racey with power from 3000rpm upwards. The second aspect of camshafts is Lobe Centreline Angle(LCA). This affects how much overlap & how early the intake opens. Wide LCAs like Volvos stock cams produce a wide power band with good fuel economy. Narrow angles produce more peak power & torque at the expense of fuel economy & flexibility. 260degree@.050" cams ground on wide 109 degree LCA such as Phil's MPPE produce good power across a wide range & can be made to perform form idle through to 7000rpm. If you take the cam out & have it ground to 101LCA like Volvo rally cams it will become peaky & produce more power & torque in the 3000-6000 range at the expense of being a pig around town, being undrivable under 2000rpm, idling badly & eating more fuel. Thirdly is lift, high lift produces more power & torque without affecting economy & drivability, but the cost is they don't last very long.
Cheers,
Paul.
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