Bolt and washer, engine plate to frame, Norton Long Road Holder singles and twins (brazed cradle frame) 1947 to 1957+ 2 required per machine, 7/16". The same part number was used for the bolt but the head shape changed when LRH were used. The LRH had a domed head - the girders had a hollow head.
Original part number:
E4268 - Rear engine plate frame attachment bolt
E5377- Rear engine plate frame attachment bolt washer