Cast iron 3 5/8 -bore cylinders offer a lower cost alternative to engine builders. Available in two lengths: standard for stock strokes (3 31/32 , 4 1/4 ) or 4 3/8 flywheels, or +.200 longer for use with 4 1/2 , 4 5/8 or 4 3/4 stroker kits. Fit Shovelhead models from 1966 thru 1984. Sold each without pistons.