how much cam

To get the correct lift for you current cam (.501/.513 with a 1.6 rocker) just divide by 1.6 to get the lobe lift, then multiply by your rocker ratio to get actual lift: example 0.501 / 1.6 = 0.313125, then, 0.313125 x 1.7 = 0.532 lift. So, your current cam is 0.532/0.545 lift, new cam would be 0.566/0.571 lift with a 1.7 rocker (instead of 1.6).

When comparing cams duration, always start with the 0.050 numbers to get an apples to apples comparison. What you are referring to as "actual" duration is the advertised duration...which I think comp does at 0.015 or something like that.

What does it currently run (ET, MPH, 60')? Just looking at the advertised duration numbers, I would guess those cams are VERY similar in duration.