Edelbrock StepUp Springs w/ 20 vacuum

I like to bring a vacuum guage inside the car and monitor the vacuum in high gear and a light load at cruising speed 55-60. Then start jetting down a couple thousandths at a time until a lean surge develops. Then jet back up a couple thousandths. Now you’ll want the springs to give you enrichment just below the cruise vacuum that you noted earlier. You can stretch the heaviest spring and or add an ink pen spring inside the original spring. Whatever it takes. This will make your engine crisp. In fact if you drive in the winter you may have to put a richer metering rod in to help out a cold engine.