What can ya do?
James,
While you are waiting to retime your engine you might want to work on cleaning up the airframe. If you don't have retracts, install some. Add gear doors, seal hinge lines, smooth out anything that even looks draggy. Next you want to use a speed prop. That 7 or 8 pitch isn't going to give you speed with large low-rev engines. You need a 10 pitch minimum. Try a 10x10. If you use this prop you will need more runway to build up speed before rotating. Once you are in the air use smoooooth turns to keep the speed up. Next, hold on, have fun, let me know when your knees stop shaking after the 1st high speed pass.
Mark