The Complete Builder's Guide to Hot Rod Chassis & Suspension

PREFACE

The author’s $105 1930 Model A coupe, circa 1960. It represents the start of his lifelong career in hot rodding, most of which would be spent owning at least one Model A Ford in one form or another. This is the car that started it all, and it’s evil ride characteristics prompted a decades-long quest to find a truly comfortable, effective suspension/chassis setup for hot rods like it.

I moved from Van Nuys, California, to Northridge, California, in 1959 and, being a car enthusiast, the first thing I noticed was that all of the older kids in the neighborhood had Model A Ford hot rods. I thought the cars were really cool, so I worked odd jobs in the area until I had enough money to buy a Model A Ford. I purchased a nice 1930 coupe in 1960 for $105, and that was the start of my hot-rod hobby, and as it turned out, my occupation. During the 1960s, I built a number of Model A street rods, but the one thing they all had in common was an uncomfortable ride.

After owning a variety of early Fords, in 1967 I purchased a 1928 Model A Ford coupe that I planned to turn into a show car. When I was finished with the car, it featured a chrome-plated, dropped-tube front axle, and the rear end was a chrome-plated Olds differential that came out of K.S. Pittman’s 1940 Willys gasser race car. The differential had all of the race-car mounts, so I set it up exactly the way it was in the Willys, hoping the ride quality would be softer than that of a stock Model A. It was an improvement, but it remained stiff. Obviously, the car hooked up well with the race car setup and rear slicks. When the coupe was finished, it was a really nice-looking car, and it did win its class at the World of Wheels car show two years in a row.

When the coupe was in the building stages, several of my hot-rod friends and I formed a San Fernando Valley hot-rod club called the Hard Times. In 1970, the club had a barbecue at a member’s house, and one of the new members in attendance had a Model A sedan that had just been equipped with a Jaguar independent rear suspension. He was touting the virtues of the Jaguar suspension, so I asked him if I could go for a ride in the car. He said, Sure, so I jumped into the sedan and went for a spin around the neighborhood. The owner wasn’t kidding; the sedan had a very smooth ride and absorbed even the worst bumps. I was sold, so the following Monday I was on the phone looking for a wrecking yard that had a Jaguar independent rear suspension for sale.

The author’s 1928 5-window Ford Model A coupe, circa 1971. It was one of the first rods to sport a full Jaguar independent rear suspension setup. This uncaged, fully chromed Hamilton Automotive setup has worked wonderfully for four decades and is still under the car today. This same car is still in the author’s posession, and probably will remain so for a long time to come.

By the end of the day, I found a nice XKE IRS that was selling for $250. The installation looked complicated, so I contacted Hamilton Automotive in Van Nuys, California, because I knew that shop was installing Jaguar differentials in T-buckets. The sedan that introduced me to the Jaguar rear still had the differential in the original cage, but, since my coupe was a show car, I wanted the unit out of the cage so that all of the parts could be chrome-plated. Hamilton Automotive’s T-buckets had exposed Jaguar suspensions then (1971), and the shop was located a block away from where I was working. Curt Hamilton and the crew did the installation, and when it was being installed, Curt showed me the engineering that went into one of his installations. His slogan was Bullet Proof, and the unit certainly was when he was finished. When I took the coupe for the first drive with the new Jaguar differential, I was extremely pleased with the ride and handling of the coupe, not to mention how nice it looked. I still own that coupe, and it was upgraded a few years ago. In the process, I updated it with a Heidts independent front suspension. I am sold on independent-suspension systems in early-model street rods. I am also aware that if you are building a car to fit into a certain period style, the I-beam and tube-suspension systems are the only way to go. In this book, I show a variety of suspension/component installations on the front and rear of a chassis. At the end of the book, a comprehensive buyer’s guide lists the places where you can find the parts to build your own chassis or buy a new one.

INTRODUCTION

Hot rodding is a hobby that started in the late 1930s, but this book covers hot-rod chassis from the later era—the mid 1950s forward. Over the years, there have been a number of improvements in chassis construction. In the early days, you had to use Ford parts; later, aftermarket hot-rod parts companies appeared, and today, new products are being created by these manufacturers. This book covers both I-beam-style suspension systems and street-rod independent-suspension systems for the front of a street rod. I also cover rear-differential installations and independent-rearsuspension systems. This book starts by looking at an original late-1950sstyle chassis, and also shows you some professional chassis that are currently being built.

This book contains everything you need to know about hot-rod suspension systems. In it is information for you to build rear-suspension systems the correct way and to install a suspension system into your chassis properly. The I-beam and dropped-tube suspensions are the standards used today for traditional street rods (such as ’32 highboy roadsters and most highboy-style early street rods), because nostalgic styling has returned to the hobby. The independent-frontsuspension (IFS) system is the standard for 1935-and-later cars, because you can’t see one under the fat fenders, so I show you how to install an IFS unit into a street-rod chassis.

A Brief Hot-Rod History

A question that is asked often is: When did the hot-rod hobby get started? The term hot rod dates back to the late 1940s, when Pete Petersen named his automotive publication Hot Rod. Before that, the modified roadsters and coupes had a variety of names, one of which was Gow Jobs.

The origin of hot rodding can go back to the late 1800s, when Henry Ford started building horseless carriages. Ford built his first quadricycle in 1896, because he thought a motor-powered carriage would be better and easier to use than a smelly horse-driven carriage. The unique vehicle was amazing, but he received almost no publicity, so only a small number of people knew of its existence. Over the next few years, Henry Ford built several horseless carriages, each vehicle being more advanced than the previous ones. Finally, in 1899, Ford was receiving some desperately needed publicity, and a variety of wealthy investors noticed his new invention and wanted to get involved.

In an effort to get more publicity and the required financial backing that he needed to start a car company, Henry Ford raced a stripped-down horseless carriage that he built in 1901, and that modified race car certainly could be considered one of the earliest hot rods. After winning that race, Ford received the notoriety he needed to get the financial backing to launch his own car company. Ford was quick to realize that the emerging interest in auto racing helped to sell cars, so he constructed another racing car that was basically a chassis with an engine, and Barney Oldfield drove it. The early race car set an unbelievable and breathtaking top-speed record of 64.5 mph in 1903, and that set a precedent for the dry-lakes top-speed racing events that followed years later. During this same period, Louis Chevrolet was also building race cars, and I have to say that some of the stripped-down cars he built could also be considered early hot rods.

Most of the early automobile manufacturers built and raced race cars for publicity, but there were a number of other people—early car enthusiasts—modifying cars for their own use on the street and in emerging racing endeavors. Some of the enthusiasts wanted faster cars, while others just wanted their cars to look nicer than the factory models. A milestone in hot rodding occurred in 1932, when Ford released its first flathead V-8 engine, but it wasn’t until several years later, when dry-lakes racing started to become popular in California, that the sport took hold. The lag between Ford’s first flathead V-8 engine and the dry-lakes racing was the time it took for the cars to become affordable for teenagers and younger enthusiasts.

It is interesting to note that the flathead V-8 engine was being tested in 1930 and 1931 and was originally scheduled for release in 1933. Model A Ford passenger-car sales were dropping in 1930 and 1931, due to the Great Depression, so Henry Ford thought that if the V-8 engine could be introduced earlier, it would stimulate more sales and make the company more money. The Model A was supposed to run with only small changes through 1932, so Henry installed the V-8 into a Model A to see how it worked, and the result was a car whose chassis flexed and twisted a little from the additional power. The stock Model A engine was developing 40 hp, and the new V-8 engine was developing 65 hp, but that was enough to create noticeable chassis flex. Henry told his son, Edsel, to make the necessary changes to the Model A chassis to handle the additional horsepower. Edsel could have easily done that with some additional chassis gussets, but, being a designer and stylist, he took advantage of the assignment and created an all-new car with a sturdier frame. The frame rails were exposed, and that eliminated the need for splash aprons; the bodies were similar to the Model A’s, but they had refined lines and no sun visor. When Edsel made the changes, every body style available had to be changed, and that was a huge undertaking, considering the number of bodies being manufactured and offered for sale. The ’32 Fords were great-looking cars, and the V-8 engine did catch everyone’s attention, but the big change was very expensive, wasn’t really necessary. And since many people were out of work and couldn’t afford to buy a new Ford anyway, the end result was that the Ford Motor Company lost $75 million. Thanks, Edsel!

Sales of the ’32 Ford were low, but enthusiasts did like the new V-8 engine, even though it had a lot of problems in the first year, they saw plenty of potential for creating additional horsepower. Ford engineers continued to improve the flathead V-8 engine, and it didn’t take long before the engine became reliable. Performance enthusiasts and automotive engineers at the time began to develop performance parts to improve the horsepower of the flat-head V-8 engine, and that activity became the start of the speed-parts industry. Enthusiasts found out that increasing the engine’s compression ratio and changing the cam profile improved the engine’s horsepower. When those changes were done, the engines could handle more gasoline, so multi-carburetion was needed.

The young enthusiasts modified their engines and tested them on California’s dry lakes to set top-speed records. The dry lakes were popular, because they were perfectly flat and long, making them the perfect places to test the cars’ top-speed potential. The Ford flathead was one of the racers’ favorites, but enthusiasts brought out a variety of different cars with four-cylinder and six-cylinder engines. Soon, the Southern California Timing Association (SCTA) was formed to sanction this new style of racing, and dry-lakes and salt-flats racing is still going strong today. The SCTA came up with different classes for the cars that were racing and started keeping the top-speed records. Dry-lakes racing was growing in popularity in the late 1930s, but World War II interrupted it.

Many Southern California dry-lakes racers joined the armed forces and were getting correspondence from the SCTA and other friends about the dry-lakes racing that was still going on, and those soldiers were telling friends about the fun they were having before the war started. Before long, other soldiers became interested in the hobby. Many of the mechanically astute fellows who’d joined the Army, Navy, and Army Air Force became mechanics and fabricators, and in their positions they learned many new tricks that they used on their cars when they returned from the war. Many of the young men learned how to weld, work machine tools, and fabricate parts out of blocks of steel and aluminum. Some of the fellows who joined the Air Force or Navy were trained to work on airplane engines, and the engines were far advanced over their automotive counterparts, so many of these men learned how the airplane engineers were building horsepower. The fabrication and mechanical skills that the young servicemen learned in the service were used later when they came home and started working on their cars.

After the war ended, many soldiers returned to California, and dry-lakes racing became even more popular than it was before the war. It was at this time that many of the stripped-down, dry-lakes race cars were also being driven on the street. Some of the cars were beaters that were only meant to go fast, while others were nice-looking cars as well as fast. The racers started lowering the cars to get less air flowing under the body, which helped the cars’ stability at speed. The old, skinny tires and large-diameter wheels were replaced with 15- and 16-inch steel wheels and wider tires that improved the handling of the cars.

It was evident that many of the emerging young car enthusiasts were fascinated by the appearance of the racing roadsters, but dry-lakes racing didn’t interest them because the California desert was dusty, extremely hot in the summer, and very cold in the winter. Pictures of the custom-built roadsters started appearing in publications, and before long, enthusiasts all across the country wanted to build a car that looked like a dry-lakes race car, even though the closest dry lakes were thousands of miles away. Many of the enthusiasts built street-driven cars that resembled the race cars, and they also spent money getting the engines running strong and the cars looking nice. Hot rods may have started in California, but it didn’t take long for the hobby to grow throughout the United States and, eventually, beyond.

The original dry-lakes race enthusiasts liked ’32 Ford roadsters because they were low priced, lightweight, and, most importantly, already set up to run flathead engines and 3-speed manual transmissions; so it was easy to swap in the stronger-running later-model engines and transmissions. Roadsters were low priced, because most car owners preferred cars with windows. Starting in the days of the Model T, most people wanted enclosed bodies, and the overwhelming sales leader year after year was the two-door sedan. The interest in closed cars didn’t change in the 1940s and 1950s, so enthusiasts started modifying coupes and sedans, using the styling features of the dry-lakes race cars.

Modifications included lowering the front and the use of modern wheels and tires. Some of the dry-lakes racers also started to race coupes, and they found out that chopping the top made them go faster. As I mentioned earlier, the number of ’32 cars produced was low, so