For Reedy its the 737 stand up or 767 lay down. For Trinity its the 4383 Stand up.
That said you cant run any of those in a Reedy or Trinity motor. By design the V2 can get away with very aggressive brush compounds. Conventional motors burn up the comm and loose power at about the 2 minute mark with those brushes.
You need Reedy 729 Quasar stand up or 766 Actron lay down brushes. They are made from a compound that help keeps the motors going for a full 5 minutes.
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series