KEITH BLACK PISTONSPart Number : KB272 KB272 KB Performance Piston Kit - 3.498 in. Bore/9:1 Ratio Originally designed by Keith Black, these pistons provide a tighter fit and longer piston and ring life Made from high-strength T6 heat-treated, 390 hypereutectic alloy, then diamond-machined and held to plus or minus one gram weight and less than one-half-thousandth-inch (.0005") tolerances from piston to piston Each kit contains two pistons, pins, spiro-lock pin clips and Hastings moly rings Replacement rings also available separately Part no. H1310R (enough for two pistons) Replacement spiro-lock pin clips Part no. 148980 (4pk) Made in the U.S.A. Fits XL 883 to 1200 conv. 88 and up (reverse dome) 10.0:1 comp Available Sizes: 3.498 in./Standard - Part No. H13203 3.503/+ .005 in. - Part No. H13225 3.508/+ .010 in. - Part No. H13224 NOTE: KB pistons can be installed tighter than other pistons. This results in less piston rock and better ring seal. Please read instructions furnished with piston for correct piston clearance NOTE: Due to the thermal conductivity and design of KB pistons, special attention is required to the top ring end gap. Please read instructions furnished with piston for correct ring installation.