March performance vs cvf pulleys on 340

Before you pull the old pulley measure from a flat spot on the case to the center of the grooves. Then press on the new pulley until you get the same. Easy as ....but if you want it perfect so as to match the new pulleys you need to measure the pulleys with strait edges and from flats to the center of the v-grooves (the center of the v-grooves from the mounting flats of billet pulleys may be different than that of oem steel)