Drag Racing Tips?

Think I'm Ready To Take The Dart On Its First Passes.
1970 340 Swinger-preety Hot Cam-shift Kit(727)-holly High Risew/750 Carb- And What Must Be 4.10 Gears In A Sure Grip Rear End.
Just Street Tires (81/2 ") My Concern Is The End Of The Race When I'm Well Into 3rd Gear. This Car On The Hiway Is Really Reving At 60 Mph. Whats Going To Happen At Close To 100mph. No Tach So I'll Shift By Ear (probably Early). You Guys Do This Every Day, So What Can I Exspect At The End Of The Race? I'm Projecting High 13 Times But Don't Want To Hurt The Car. Ant Thoughts? Thanks