Don't put 50 timing on a 7.5T motor. That will push it way too hard. Mod motors don't benefit from pushing to the limits like stock motors do.

As far as the OP is concerned, if the ESC setting are "default" on both ESCs, how do you know that they are the same? Comparing apples with oranges. You need to spend more time setting your equipment up, or at least understandig how your equipment is set up. There's no reason for a significant difference between the motors, if anything the Surpass should be faster (when geared right) as the rotor will be a lot stronger.