After talking with SumerMarioBro here is the new EV spread for Bulky DD Gyarados: 88 HP / 168 Atk / 252 Spe, with an Adamant nature. HP EVs give a lefties number and prevent Jirachi from breaking your subs with Body Slam, while the Speed lets you outspeed Choice Scarf Terrakion and Keldeo at +2.
Please also include the Scarf set that SMB posted and the CB that i did.
Part of the OU QC team, message
me for a check!