Review on Holley 20-13 Secondary Diaphragm Spring 🔧 Kit: Maximum Performance Upgrade for Reliable Engine Efficiency by David Gibbs

Not available in retail packaging. The connection to the included spring is non-holly and provides reverse rev range opening and full opening. Does not include Holley instructions. I don't think this is a real Holly set. All the characters look like it's a fake packaged and sold as a holly. The feathers themselves look good. Time will tell if the quality is right.