[Adam C.]

And now for the final installment of our engine tuning trillogy. The items that we have left to look at are the camshaft, compression ratio, and displacement. The camshaft has several parameters, leading to an infinite number of possible combinations. Here we look at the major parameters one at a time.

First up is cam lift. Most magazines say that it is pointless to run a cam that has more lift than that of the cylinder head at max flow.

Here we vary the cam lift by 10% up and down from our good old FMS X303 cam. The engine is still our 5.0L described earlier, with the single plane manifold and TFSR's.

It is important to note that while our heads in this simulation flow as well as the TFSR's, they still have the small 1.94" intake valve of the GT40X. This means that the max flow is still realized at about 0.5", where the real TFSR's attain max flow at about 0.65" I think. This means that to get the results that we are showing here, you need to run a cam with more lift than the X303.

For our comparison however, the lift of the X303 is about .050" higher than the max flow of our physically impossibly ported GT40X's, so it will still work for comparison.

In this case, the magazines seem to be pretty accurate. There is almost no difference in vol eff with the lift varying a whole 0.1". It should be noted that all three of the lifts tested were at or above the head max flow lift. Going below this will hurt power.