On October 7, 2012 a Merlin 1C (Engine No. 1) of the CRS-1 mission experienced an anomaly at T+00:01:20 which appears on CRS-1 launch video as a flash.
SpaceX was planning to develop a 560 kN version of Merlin 1C to be used in Falcon 9 block II and Falcon 1E boosters [REF].