Need more info.
What is your idle RPM?
What is your initial timing set at?
If you have vacuum advance, are you connected to the Ported or Full vacuum fitting?
What stall speed are you running?
What trans are you using?
What rear gears?
What diameter rear tires?
When stomping on the "Go pedal" at 50-60 does it spit back thru the carbs or just fall on it's face?