sonic 500 kit question
I would actually try a different prop. We routinely run these types of planes with the O.S. .46fx and a 10x7 is just a little too much prop. You want them to turn up a little more if your looking for speed.
We have found the following props to work best on .46 sized engines in this class:
APC 9 1/2" x 7 1/2 N
APC 9x7 Sport
APC 8.75 8.75 W
APC 8.8 x 8.5
Speeds should be between 110 - 120 mph on the course.
Good luck.