I don't have a 74HC164 on hand to try and I'm not 100% sure from reading the datasheet.
If for example I've got a bunch of LEDs lit up from the outputs of the 164 and I pull the reset pin LOW will
A) all the outputs be immediately set to LOW as soon as I pull the reset pin low
B) all the outputs will keep their current state until the next clock pulse when all the outputs will be pulled low.
I'm waiting on some of these to arrive in the mail to experiment with but would love to be able to get my schematics in order while I wait. Thank you!