In another thread we were debating the use of a small Holley 4v carb on a 302 to gain mileage. If you think about the stock 2v carb being around 300 cfm, then you can figure it is relatively ineffiecient using those 'large' venturis in every driving situation. A Holley 390 4v will have 180 cfm in use during driving. The other 180 cfm, to make the extra power over the 2v carb, is vacuum operated and comes in only when needed. ANYWAY... This is not what my post is about. It is just what led me to check Summit for the options on new 390 Holleys. I found one that I like and one of the links on that page was: http://static.summitracing.com/global/images/instructions/hly-0-8007.pdf What I like so much about this document is that it explains the function and sensible tuning of Holley 4v carbs very well. The instructions with carbs never used to be so detailed. You used to have to buy a book to get some of the details in this PDF. Anyway, if you always wanted to understand Holleys, or wanted the info in easy terms, you should go to and save this link. It starts out as install info for a 390 carb, but then becomes more and more universal to 4150/4160 carbs in the fine tuning section. Dave
Thanks for the good info and homework on your part . Imo, Holleys are the only option and once you learn the basics, they become very easy to work with.
Very awesome article, thanks a lot! I must say, my holley "class" was a 15 minute how-to before I jumped in the seat of my first race car, the Mustang. The only thing I was comfortable with was idle speed setting and jet sizing. I might have to do some messing around once I get the stang back into action. Thanks again!
