here you go psca 2014 weight brakes if this is not proof. I can look up the nmca rules for you to. DEDUCT WEIGHT (In Percent of your Engine Cubic Inch Displacement)
10% For Single Carburetor Applications
10% For Pre-74 Full & Mid-size Entries
15% For a 2-speed Automatic Transmission (Big Blocks)
20% For a 2-speed Automatic Transmission (Small Blocks) it 1s at least a tenth maybe more. most people will not spend the time or money. to make a three speed work they will usually ride the wheelie bar to hard and kill ET a three speed with a flat first like a 2.08or 2.20 is where it is at for a small block