More cam crud......explanations please!

[scourge at cogeco.ca (Scourge)]

Okay, so I'm looking to get a cam for my car(86 8V JH), I was thinking just a G-Grind or similar. Now I'm thinking maybe go a little further, but I really have no idea what difference Lift and Duration make. Obviously with higher lifter you can get more flow.
For example
"286 degree .436 lift.
"Sport Solid Lifter"
13 horsepower gain. Aggressive idle."

What's the 286? Does this mean the valve will be open for 286 degrees of the cam rotation? With a cam like this will the intake/exhaust valves have the same lift/duration??

I really have no idea, can somebody give me the lowdown on what these numbers mean and how they will affect the car while driving??

Thanx
-George

PS. For reference, the cam info came from http://www.concept1.ca/engine%20cams.htm