I'm not sure completely of your intent, but I think you want to use a 3dcalc command. What you were looking at was simply the mask which has only a value of 0 or 1. I assume you would like to see the values in some functional dataset but limited within a mask. So let's say you have an F or t value in sub-brick 14 of func+orig, and mask+orig is the result of the 3dautomask command, you could use the following command to limit the data

3dcalc -a func+orig'[14]' -b mask+orig -expr 'ispositive(abs(a)-50)*a*b' -prefix threshfunc

This will create a dataset thresholded with absolute values only above 50. You can instead leave off the "ispositive(abs(a)-50)" part leaving just "a*b" and use the thresholding slider in the AFNI overlay in the AFNI gui to change the values interactively.