ralphsmithiii

Found what I was looking for. Thank you internets!

Michael_D

Valve lift - the total lift including the rocker ratio. The card will usually tell you what ratio that lift is at. Make sure yours indicates a 1.8 ratio.

Duration at .050 is the lobe duration in degrees from the .050" lobe lift points on both sides of the lobe. There was a time when "advertised" duration numbers were given, but there was much discrepancy between manufactures as each one would reference different lift points on the lobe, so you couldn't ever compare cam profiles. The .050" standard was then instituted. A few years later, manufactures started noting advertised duration at .006" lift. I prefer to know the .006" numbers, .050, .100, .200, etc... Knowing all the duration lift points tells me what type of lobe profile the cam has.

Lobe separation is the angle that is represented from the lobe centerline of the intake and exhaust lobes to the center of the camshaft. As LSA tightens, valve overlap increases. Valve overlap is the time in which both the intake and exhaust valve are open during end of the exhaust stroke and beginning of the intake stroke.

ralphsmithiii

Thanks for the reply. Because of my lack of knowledge of cams, just reading up on Comp Cams website explains a few things, but I'm still unclear about how one custom cam differs from another. Meaning, when I look at those spec's, how would I know if its a "mild" cam versus a "aggressive" cam other than what the builder tells me. Not that this is about questioning my builder or any other builder, I just don't understand the numbers I'm looking at.

When someone says or I read a post about making sure to get a cam with "this LSA" or "that lift" to keep it mild mannered, that's what has peaked my interested in the numbers aspect of all of it.