[aumoore]

I have a 600 vac secondary 1850S Holley and it works great in cornering and braking but I am having a problem at the drag strip. If I start in 1st gear(SD T-5 with 2.95 first gear and 3.73 rear gears) the motor stumbles about 50 to 60 feet out at the drag strip. If I start in second gear the car launches soft but no stumble. This does not seem to be a problem on the street. I am guessing that the car will launch better at the strip due to all the sticky rubber.

I have some theories on this:
1. The fuel is sloshing back in the secondaries causing a lean condition.
2. The fuel in the Carb runs hotter due to the heat rising from the motor while waiting to run. This would be the case even if you push the motor to the staging area because the motor is still hot from the prievious run. On the street the motor has cool air flowing over the carb thru the hood scoop.
3. combo of both

I have consistant fuel pressure of 7psi and the floats are set correct. I did put a lighter spring in the secondary diaphragm but it still does this track stumble. I have tried to duplicate this on a rural road but cannot duplicate it.

Any suggestions