Cam questions Options

[ThinAir]

I'm assembling the pieces that I'll need to rebuild my 1973 2.0L engine that will retain the stock FI. I'm wondering about cam choices and why I would want to choose a particular one. The only change I've made from stock at this point is that I've got Mahle Euro pistons & cylinders, but they are stock size so there is no increase in displacement.

I hear a lot about the Web Cam 73 and here's the info I've been able to find on how it compares to stock:

Type/Lift/Duration/Duration @ .050
Stock/.392/?/210
73/.426/262/224

Am I correct that Duration is how many degrees both intake and exhaust are open? Or is that called Overlap? If it is called Overlap, does anyone know the specs on the two cams?

What is the difference between Duration and Duration @ .050?

Lift is pretty obvious - the 73 is going to open farther. I assume this means it can deliver more fuel mixture in the same amount of open time compared to the stock lift.

My car is a daily driver that will probably never see anything more exciting than a PCA autocross. So how do I choose a cam and why do I want one or the other?

[ThinAir]

Yup. Web Cam sells a stock grind for $133 (compared to $158 for the #73).

Thanks to all for the advice on this. The article at CompCams is very good. I had previously looked at How Stuff Works and they have a pretty good article, but not as detailed.

What surprised me was that I expected to see the amount of overlap as part of the specs for a cam, yet no one ever discusses it. Perhaps there is a relationship between overlap and lift/duration so that you don't need to spec overlap, but I was thinking that there might be 2 cams that were identical in both of these but had different overlaps.