Pingel Power-Flo High Volume Petcocks 6211-CH 1-1/4in. installed valve height from bottom of tank allows extra clearance when mounting tank Uses 5/16in. fuel line and has a 3/8in.-18 NPT mounting thread Fits 57-74 XL; 66-74 Big Twin (custom) Substantially higher fuel flow compared to OEM or aftermarket fuel valve Necessary for adequate fuel delivery even on stock motorcycles and a must for high performance