Cam card specs meaning

I'm looking at cam cards trying to chose a cam, the intake exhaust opening/closing numbers are printed there and I was wondering what they tell you about the cam. The Lunati and the Hughes have similar numbers. The Comp Cam, although similar duration, the intake/exhaust opening and closing numbers are totally different.

Probably one of these will go into a 408 sb with Edelbrock heads, 10.3 ish compression, 3.23 gears.

These are the specs:

Lunati 60404, dur 234/242 @ 0.050, lift .513/.533, 110,
Intake: open 11 btdc/close 43 abdc, Exhaust: open 55 bbdc/ close 7 atdc
rpm 2200-6400, advertised dur 276/284

Hughes 3237, dur 232/237 @ 0.050, lift .540/.548, 110
Intake: open 9 btc/close 43 abc, Exhaust: open 51.5 bbc/close 5.5 atc
rpm 2300-5700

Comp CCA-CL20-227-4, dur 231/237 @0.050, .525/.525, 110
Intake: open 32 btdc/close 64 abdc, Exhaust: open 78 bbdc/close 30 atdc
rpm 2000-6,000, advertised dur 275/287

BTW, Edelbrock says their springs are good to .575 lift. Has anybody had any problems with the Edelbrock springs with cams in this general lift distance?