408 build

Would a smaller cam make it more street-able? If so how do you determine the cam size, I've often been confused about the real difference between say the OP's .573 and .590 and say .566 and .583 does it really make that much difference? seems like such a small change.
Lift has a direct impact on HP. Not so much torque. The idea of lifting the valve high is to take advantage of the heads high flowing capabilities. If it has them.

Duration is where the rpm band is determined and yes a smaller cam lowers the rpm band in which it operates in. You have to be careful because a small cam has the timing events closer together and this can cause cylinder pressure to sky rocket. Thus making pump gas impossible to run.

Most cam manufacturers will list an operating rpm range where the cam should perform in. Crane goes as far as to even list the cruise rpm band in which there cam will perform in.

Most other companies will list the cams power band range. Hughesengines has a listing in there tech pages on where a cam should be making power T a min and max if you follow there suggested parts to work with the cam being used.

Without getting into cam talk, because it can get deep quick & be a little confusing, just follow the suggested parts list that the cam works with best. Cam manufacturers can play with the cams timing and ramps to come up with some pretty slick results. Unless you understand this kind of stuff, I suggest the K.I.S.S. Method.
(That would be, Keep It Super Simple)

Otherwise, you’ll end up on the phone with Comp or Crane or ..... talking about everything and then some more about the whole deal for the cam. They will want to know EVERYTHING about the whole deal. So be prepared to have every little detail about your car, trans, rear gear and tires & and wht you want to do or expect from it.

If your well prepped and spend the time on the phone, chance is, your going to be REAL happy with the custom grind your going to get.