383 motors need to rev to go fast at the 1/4 mile tracks Short stroke motors need all the help you can give them
That being said what RPM are you shifting at now?
Did you degree the cam? If so is it straight up, advanced or retarded?
If I was you I would work on the 60 ft. times, carb. squirters and traction first Is it spinning or dead hooking?
What size squirters are in the carb now and are you still using the 50 CC rear pump? If you have # 35 or bigger squirters try some # 33 or smaller and if your still running the 50 CC pump swapping it out to a 30 CC pump.