LCA is a function of duration and overlap. Increased duration with the same LCA increases overlap. So If a given combination needs more duration then LCA has to widen to maintain the same overlap. Look at the LCA of big duration cams. It will be wider for most applications.
Doug
Two things that affect the amount of overlap versus duration are head efficiency and compression ratio. An 8/1 compression motor has to clear a lot more dead volume at overlap than a 16/1 motor. Also, as cam duration goes up beyond a certain point, on average the heads will be better and compression higher. I would bet that could be demostrated by looking at some stock class cams. If i am right, they should have a longer overlap period compared to total duration.
