40, 41, 42 tooth blower pulleys are made from 2024 alum. for strength purposes due to being so thin making the purchase price higher than a 43 tooth.
For the smaller top pulleys please check the I.D. to see if they will clear the blower snout. 40 tooth I.D. = 3.450" 41 tooth I.D. = 3.550" 42 tooth I.D. = 3.570"
Racer can pick pulley size from drop down menu.