Shearing the incoming fuel is accomplished by leaving the intake seat with a tiny sharp edge left by the seat cutting tool. Fuel is sheared by this edge as the fuel crosses the seat. Installing an oversize stage 1 valve may accomlish this but never "sink" a valve for that purpose. Keep your proper stem height. A friend who built heads for circle track cars claimed 10 hp with a small block chevy on his dyno by leaving that sharp edge. Also, Speed o motive wrote a very informative article and noted this........... If a small step is added at the valve SEAT to force the wet flow over the resulting sharp edge, fuel will reenter the air stream and give you the same affect as dimpling only without losing the benefit of a completely polished chamber. As you reduce wet flow you will improve combustion and most likely need to install leaner carburetor jets. Leaner jets compensate for the excess fuel that is available when wet flow is put back into the air/fuel mix. Significant additional horsepower gains can be had with careful attention to cylinder-to-cylinder fuel distribution by allowing all cylinders to be set "just right". Read more: http://forums.superchevy.com/chevy-...uilding-tips-by-speed-o-motive/#ixzz4GnM2jwos
