You need to determine how much stack your frame/fork combination provides. The VO headset needs 41mm of stack; if you measure less than that on your bike, you'll want to look elsewhere. You can use a shorter stack headset and make up the difference with spacers, but if the headset requires more stack than what you have, you're out of luck.

To measure stack, remove the headset cups and crown race from the frame and fork, insert the fork into the frame, all the way to the race seat, and measure the length of steer tube projecting beyond the top of the head tube: