David Vizard - David Vizards Holley Carburetors: How to Super Tune and Modify

CarTech

CarTech, Inc.

39966 Grand Avenue

North Branch, MN 55056

Phone: 651-277-1200 or 800-551-4754

Fax: 651-277-1203

www.cartechbooks.com

2013 by David Vizard

All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without prior permission from the Publisher. All text, photographs, and artwork are the property of the Author unless otherwise noted or credited.

The information in this work is true and complete to the best of our knowledge. However, all information is presented without any guarantee on the part of the Author or Publisher, who also disclaim any liability incurred in connection with the use of the information and any implied warranties of merchantability or fitness for a particular purpose. Readers are responsible for taking suitable and appropriate safety measures when performing any of the operations or activities described in this work.

All trademarks, trade names, model names and numbers, and other product designations referred to herein are the property of their respective owners and are used solely for identification purposes. This work is a publication of CarTech, Inc., and has not been licensed, approved, sponsored, or endorsed by any other person or entity. The Publisher is not associated with any product, service, or vendor mentioned in this book, and does not endorse the products or services of any vendor mentioned in this book.

Edit by Paul Johnson

Layout by Monica Seiberlich

ISBN 978-1-61325-119-5

Item No. SA282

Library of Congress Cataloging-in-Publication Data

Vizard, David.

David Vizards how to super tune and modify Holley carburetors / by David Vizard.

p. cm.

1. Holley carburetors. 2. Automobiles--Motors--Carburetors. I. Title.

TL212.V39 2013

629.25330288--dc23

2013012931

Title Page:

This 580-hp Chevy 355 is visually stunning engine. The polished surface on the intake manifold contributes to the overall production of horsepower and can be an aid to your vehicles on-track performance.

Back Cover Photos

Top Left:

Holleys big-CFM Dominator was only a viable wide-band power proposition because of its intermediate cruise circuit and the use of high-gain annular discharge boosters.

Top Right:

The stepped dog-leg booster (arrow) has only marginally more gain than the regular dog-leg booster, but the step brings about better fuel atomization. This style of booster is about the most versatile currently in use and is a good choice if fuel atomization appears to be inadequate.

Middle Left:

Holleys Ultra models have an adjustable idle air bypass screw (yellow arrow). Air for the bypass goes through the holes indicated by the blue arrows.

Middle Right:

Until the main jets come into play, the engine relies on the transition slot for calibration. Here, the baseplate has been removed from the carb body to better show the butterfly position for the slots best operation. The amount of slot remaining above the butterfly is shown by the red arrow. The amount of slot as viewed from the underside is shown by the yellow arrow. The slot is open about 1 turns of the idle-speed adjusting screw.

Bottom Left:

This is the business end of the accelerator pump system. These pump jets, commonly called squirters, are available in a wide range of sizes.

Bottom Right:

In a home workshop, you can use a die grinder and some 100-grit emery rolls to do all the work on this body. The points of note are the detailed boosters with a sharp edge (yellow arrows), the rounding of the edges leading into the secondary barrels (blue arrows), and the radiusing of the edges on the choke horn (green arrows).

The author of any book worth its salt pulls information from many sources. I am no exception. Since my first real immersion in the world of Holley carbs in 1976, there have been literally hundreds of people who have taught me something about these carbs. I am sorry that I dont remember the faces and names of everybody who helped along the way over the years between 1976 and now. To all I am grateful for your contribution to my education. However, as is so often the case, there is inevitably some person or persons who turn out to be pivotal as far as routing ones life down a given path. For me, that was David Braswell of Braswell Carburetion in Tucson, Arizona.

My good friend Denny Wycoff introduced me to David. Denny was a racer and drove for several years, with great success, for J. D. Braswell, Davids dad. Denny was a very innovative racer and teaming up with J. D. was a natural, as J. D. was also a highly innovative character. Well, the apple, as they say, never falls far from the tree. Not unexpectedly, David Braswell inherited his fathers mental agility as well as a love for racing. Davids life focus was on carburetion in general and Holley carbs in particular.

From 1976 to 1980, I lived in Tucson just a few miles from Braswell Carburetion. If I had a question, David always had the time to answer in detail. If I had a question David could not answer with his extensive and definitive experience, he went out of his way to help out on whatever tests were needed to generate a detailed answer. Nothing was ever too much trouble or took too much time. So, in the production of this book, a great deal of credit must go to David Braswell. Thanks, David.

To Davids great input I also want to add that of Holleys engineering staff, past and present. Occasionally I get to work with them and for me it has always been a learning event.

Having the technical know-how at hand is only a good start in the production of a book. There are many administrative chores that need to be handled. Over the 35-plus years I have been dealing with Holley I have worked with a number of very helpful PR people within the company. I want to thank all of them. But in the last few years, and when production of the book was at its most intense, I had to rely heavily on Holleys current PR person, Bill Tichnor, and his assistant, Blaine Burnett. Every time I had an issue or problem, these guys came through. Thanks guys, your efforts are much appreciated.