I will be installing it into a Global Tequila sunrise. How does 8x6 sound?

Sounds fine, except I might suggest a 9-4 or 9-5.

Have you run the motor yet?

Tell me about it...

I have not run it yet. It will be going on the test stand this weekend weather permitting.

Most people I know run a 9x6 on their .25's.

I have a MA 9x4 lying around. Maybe I'll try that first. I hope to achieve a reasonabls amount of speed with this combo.

A 9X4 is a good break in prop for that engine & will pull pretty good but for more speed you might want to try a higher pitch 9" or a 8X7 or 8X8 prop. Just don't use one of those exhaust deflectors on it , they really restrict the exhaust too much . MAX H.