LCA is very close to LSA. LSA is figured as the angle in degrees of camshaft lobe seperation. In other words, how far apart the center of the cam lobes are. LCA is how far off center the cam lobes are. Typically, cams are installed straight up, and the LCA and LSA are the same. The alphabet cams do not follow this pattern. E303 is 107/117 B303 is 109/119. Since the alphabet cams have already been setup with an unequal LCA, they are almost always best when installed straight up. Some other cams, including the stock HO cam are better advanced or retarded in particular applications.
I don't know who came up with the idea the average automobile application has an LCA of 110*? That's what most high performance cams have. The stock HO cam, which is fairly aggressive is 116 or so. Most street cams are between 110-114 for the 5.0, anyway. Going below 110 generally begins to lead towards manual brakes, and causes idle problems with the EFI systems due to poor vacuum. On a stock EEC-V 5.0 computer system, the car probably wouldn't run for crap. Newer cams have bumped LCA and LSA up in an attempt to sacrifice a little very high rpm performance for a good idle and stronger bottom end/mid range power.
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