It mainly depends on what your goals are, the cam’s attributes, and the efforts put into the porting. Here is some of the porting results I have done on 6X heads on the intakes at different levels.
Stock…208 @.5” lift
Bowl porting…
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Bowl and Ceiling porting…
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Porting,Jim Hand
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2.11” valve, RA4 ports, tall ceiling, short side work,
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2.125” valves, RA4 ports, short side work, tall ceiling
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2.125” valves, RA 4 ports, short side radius turned sooner, ceiling matched to short side,
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