In a nut shell....
Most of the cam grinders give duration at .050 lift. Some in advertised duration. The differance is in order to accuratly measure the duration they use .050 lifter lift off the cam. You come up with a smaller duration than advertised but it is more persice on how the cam performs.
Lift is just that...how much the cam will lift the lifter (and valve)
Lobe center is how the cam idles and the power peaks or slopes. A low number...like 106 to 108 lobe center will cause a very rough idle and a peaky power curve (Drag race, mud bog) A 110 to 114 lobe center will be a mild to near stock idle with a more even, broad power curve. (Street driving, trail, towing) This number isn't in most mail order books...you have to ask for it.
Everyone is always bragging about the lift and duration of a cam. The fact is you can have two cams with very simalar number and have totaly differnent motors. A motor with a bigger lifter (Chryser, AMC) can have a more aggrasive ramp than one with a smaller lifter (Chevy). This is because a bigger lifter dosen't "dig into" the cam as it rotates around. Chevy races used to bore out the lifters to a (Chryser) lifter and have a custom ground cam made to take advantage of the longer duration they gain.
There are thousands of ways to grind a cam, its always a compermise to what you want. Tons of power on the bottom end = less power at high RPM. Lots of power at high RPM = crapy idle and power at low RPM.
Call up Comp cams and order a catalog...they have a real good chart explaining everything better in the front.
Always call several cam grinders and tell them exactly your combo and then pick the one you want from them...the numbers will vary. Some will pick a cam out of the book...some will make a custom grind. You can ask for a custom grind also...it costs alittle more though.
I know alot of people that just throw in a big cam that sounds great but dosen't have all the goodies that go along with the cam...right rear gears, right size carb (Not to big and not to small) headers, right intake (single plane vs dual plane) timing, higher stall convertor etc.
I have personaly blew away a $13,000 454 chevy chevel and countless 350 chevys with my old '74 Hornet with a 360. God, I wish I still had that car!! Granted I had two 450 holleys but I still pulled 10 MPG town and 15 Highway. It's in the combo man!
My new 500HP 401 I called about 4 cam grinders untill I found one I liked, I ignored the ones that took a cam grind out of the book becuase my 401 is totaly custom and I had flow numbers for the heads. (Helps alot with cam grinders getting a good grind)
Look here http://www.hottr6.com/triumph/CamBasics.html
and http://www.mousemotor.com/cb_1.htm
