i believe your talking about lobe seperation .. 110*,112*,114*
The point the cam grinder gives may be just a be the split overlap (straight up) location. Isky, to my knowledge does not grind cams with an advance ground in unless it is specified on a custom. If the grinder feels the cam will perform better advanced, they may grind it that way. Where the point actually belongs is a matter of everything from engine CID, the entire induction, compression, rod ratio, trans type, car/boat, weight, use, gearing, etc,etc,etc. And this is where a guy like Cstraub earns his $$$$Not lobe sep. but a cam card may read : intake opens at 27* BTDC Closes 70* ABDC Exhaust opens 77 BBDC Closes 26* ATDC. That's part of lobe sep.
The question is, what parameters are used by the cam grinder to determine the desired opening point as far a degreing in a cam. You may need to advance or retard your cam a few degree's to match the cam card. Why is it desired to open the intake at 27* as opposed to 24* or 32* BTDC ?
I hope that makes sense bulb
Back in the 60s, cams weren't ground with "advanced". And the vast majority of the cam purchasers just grapped them and slammed them in. Then along came Comp Cams, with there "Energizer" series of cams, and sold the living hell out of them. What made them different? Well they may have had a little quicker ramp, but more than any thing, they were ground 4* or more advanced in most cases. Why? Because they knew that a huge number of buyers were buying cams too big for their motors, and knew that if they advanced them, they would run better, mainly on the street. Many of them had wider LSA also. And they made a huge name for themselves. No cam needs to be "ground" advanced. It is all in where you install it. The cam manuf. may know a certain profile works better advanced in most cases and grind it that way. Companies like Isky don't play that game except on cams for a certain application, like upgrade cams for 5.0 fords and LSs with minor mods and EFI. IMO true racing cams should be ground straight up and let the engine builder and cam grinder decide how it should be installed.Speaking of "advance being ground in"...
What is the real reason behind cam manufacturers make some cams that have advance "ground in"? I have the Comp Cams XM278H cam and that one has 2* ground into it (112 LSA, 110 ICL, 278 int/292 exh @006", 234 int/244 exh @ 0.050"; 564 int/568 exh lift).