[Tim Votaw]

In addition to the baffles (and jet extensions in the secondary to counteract acceleration starvation), there is an old drag racer trick that I might recommend trying.

Take a piece of rubber or pvc fuel hose the correct diameter to slip snugly over the two float bowl vent tubes that rise vertically on each end of the carb opening, creating a mildly curved bridge between them. Carefully notch about five little cuts in the middle of the bridge, maybe a half-inch apart, only deep enough that they open a bit when bent into place.

This allows the bowls to vent as designed, but prevents (minimizes) the tendency for fuel to slosh up through the tubes under G's and slop into your venturis.

Wish I had a pic of this, but I think you get the idea. Some guys even go so far as to carefully bend up a piece of soft copper or alum. tubing to make this bridge, and drill the vent holes into it. A little neater than a hunk of hose.

TimV.