These big bore pistons work with the stock 4" stroke flywheels to convert any 1999-'06 HD? big twin engine from 88" to 97" displacement with 9.7:1 compression with stock heads. Stock cylinders may be bored to accomodate larger pistons, but we recommend S&S 3.927" bore cylinders which feature high strength alloyed cast iron liners. Pistons are compatible with stock rods with tapered wristpin ends. S&S? 3.927" bore pistons are machined to such close tolerances that it is not necessary to measure the piston. Just bore cylinders to nominal diameter +/- 0.0005" for correct clearance. Additionally, the low friction coating on the piston skirt makes taking measurements very difficult. 3.927" +.010" bore.
        
      - air_freight_prohibited:
 - false
 - not_carb_approved:
 - true
 - carb_acknowledgement_required:
 - true
 - ltl_freight_required:
 - false
 - prop_65:
 - Unknown
 - part_type:
 - powersports
 - epa:
 - N/A
 - regular_stock:
 - false