Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 3
Before any suspension is removed from the Corvette, it is a very good idea to record how everything is mounted to the car. Now with digital cameras, I always take pictures of any demolition, modification, or repair for future reference. In the case of the Corvette suspension, I recorded on paper the dimensions, angles, and location of all parts mounted to the frame of the car. I did not have a digital camera then. You might think you will remember every detail, but I can guarantee that you will forget something important. It is said that a picture or detailed sketch is worth a thousand words. I believe this from years of experience.
The first step was to remove the motor and transmission from the car. Now the front suspension can be removed very easily. No cutting tools are required for the removal. The front cross member is bolted to the main Corvette frame. The cross member also has the mounting for the motor mounts. This is so well designed, that all of the front suspension components are attached to the front cross member with the exception of the upper shock mounts. I will come out of the car as a complete unit.
It is important not to discard any items from the Corvette. Every single part removed can be sold. This is what I did. I listed many parts on eBay and sold many items locally. This eventually paid for the car and made me even more money. I managed to pay for the engine hoist, engine stand, and a new Millar Mig welding machine from the proceeds of this car. I even put some money in the bank for my next street rod part purchases. Don’t forget, I still have the Corvette suspension, engine, transmission, and many other parts needed to build my street rod. I never thought building a street rod was so profitable.
Next I removed the rear suspension. Again, everything came out without any difficulty. Make sure you keep the bolts. The bolts are all hardened bolts and might be required to mount the suspension in the new Model “A” chassis. I even removed all of the emergency brake cables, and aluminum brake line splitters.
The front and back sway bars and mounts should to be removed and stored. One of my main goals in the design of the new Model “A” Ford chassis was to use as many Corvette parts as possible in my street rod. This makes the long term maintenance of your street rod very simple. Corvette parts will always be available whereas custom made parts will be hard to replace when items break or wear out. Some of the custom parts built today might not be available in the future depending who originally made them.
C4 Corvette suspension as removed from the 1986 Corvette Indy Pace car convertible.
I placed the front and back suspension units on a skid and wheeled them off to my shop. Now I needed to decide on the details of the chassis design. I felt that for my first street rod, I would not be too radical in my design. In some sense, I did select something out of the ordinary by using C4 Corvette suspension on a 1931 Ford Coupe. This will complicate the design enough and slow down the building process when compared to using traditional parts in a street rod.
C4 Corvette rear suspension as removed from the 1986 Corvette Indy Pace car convertible. As few parts need to be replaced due to the accident the car was in.
I decided to use the same wheel base of 103 ½” as the original Model “A” Ford for a 1928 to 1931 frame. The mounting of the rear suspension required a narrower frame width. It was like the C4 Corvette design engineers considered the Model “A” Ford in their original design applications. The width of the rear frame rails would be narrow enough to fit between the rear body frame rails. I would only need to make a slight modification to the body frame rails to facilitate the new suspension and chassis.
C4 Corvette front suspension as removed from the 1986 Corvette Indy Pace car convertible. Everything will be removed from the front crossmember. I will use the front crossmember for the basis of my design and measure everything on it.
I measured the mounting distance between the upper control arms on the Corvette cross member. It was slightly wider than the original Model “A” Ford frame. It is important not to change any part of the original design of the suspension of the Corvette. Any changes will affect the eventual performance in handling and ride of the street rod. In some street rod applications, the entire Corvette front cross member can be used as is. It is not possible for the Model “A” Ford. I suppose some car builders would say sure no problem, use it as is. I feel the front of the car would look very ugly and be poorly designed and this option was not for me. It would be similar to builder using an original Mustang II suspension with the large coil springs. In a small car like a Model “A” Ford, this will not look good. Again maybe in larger street rods with the front ends closed in more would this be okay.
C4 Corvette front cross member stripped down and ready to have measurements taken from. The new street rod cross member will not look anything like this.
Now I had a basic design concept for the new chassis in place. The original wheel base would be adequate, and a new width at the center lines of the front and rear suspension was determined. Now, I needed to buy the steel for the new chassis.
Fortunately, in our town, we have a steel supplier. I purchased 2” x 4”, 0.1” wall thickness rectangular tubing. Before my purchase, I completed rough sketch of the new Model “A” Ford chassis. From my sketch, I calculated how much material was required for the main frame rails, rear of the frame, and the new front cross member. At the steel supplier, I had them cut two sections of the same length of tubing for my new chassis. We loaded this into my trailer and headed back home to my shop.
The next phase of the project is to complete a mock up of the new chassis with everything only tack welded.
More to come soon, including pictures of the design process. Make sure you book mark this site and come back for weekly updates.
Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 1
A few years ago when I first came up with the idea of building a hot rod, a friend of mine told me that the project will change throughout the time of the build. I did not believe him at the time, and have started to realize the truth in what he mentioned to me. Remember, I started out with 2 cars, a 1930 and 1931 Plymouth. Now I have a 1930 Ford 5 window coupe.
I started looking at the old vintage Model “A” Ford frame that came with the coupe. When I was moving it around the shop and yard, I noticed that it was not very solid. There was an incredible amount of twist in the frame whenever I picked it up from one corner at one of the ends of the frame. This was not acceptable for a modern day street rod. This might have been okay when the car was first built from 1928 to 1931 with an engine having only 40hp. Most small block Chevrolet, Ford, and Mopar engines have approximately 200hp stock depending on the model. This is 5 times the horsepower of the original Model “A” engine. Add a few engine modifications and all of a sudden you have over 400hp or ten times the horsepower of the original Model “A” engine. Some builders would say sure use the frame, but box it in. The original frame is a “C” channel frame with the cross members riveted to the side rails. Over time the frame gets a bit rusty, and the rivets will not be a tight as when the frame was first built. The front cross member often will have stress cracks. Boxing in the “C” channel requires welding a fitted metal plate to the inside of the side frame rails. If this is not completed carefully, the frame will warp and loose its alignment. This is not acceptable or safe. I have had builders come to my shop wanting to purchase the original frames for nostalgic purposes. This seems a bit contradictory if you are using any type of modern engine including an older flat head V8 engine. This in my mind is simply not safe and these sorts of builders give hot rodding a bad name when they build cars without any consideration for safety. Lately, many street rod builders would call this rat rodding. I have seen a few so called Rat Rods, in some very large international car shows that look to be absolute death traps. Don’t get me wrong, I like a well built and safe Rat Rod. I suppose you will hear all kinds of theories on this topic, and I have only expressed my opinion on the subject.
I started looking at commercially made chassis’s / frames for street rods for my application and noticed that many consisted of 2” x 3” or 2” x 4” steel rectangular tubing. There were many variations for different types of front and rear suspensions. It was time to do a bit more reading and learn more about chassis engineering. It was back to the library and internet for me to do more research. Below are a few good reference books that I have and used for ideas.
Street Rodders Chassis & Suspension Handbook By: Editors of Street Rodder Magazine
Chassis Engineering By: Herb Adams
Boyd Coddington’s How to Build a Hot Rod Chassis By: Timothy Remus
Petersons Hot Rod Year Book No. 13 (I bought this book in 1975 and there is an interesting section on how to build a Street Rod using a Bucket “T” body)
How to Build a Sports Car For as Little as 250 Pounds By: Ron Champion
Street Rodder’s Handbook By: Frank Oddo
When I mentioned to my friend, the one I obtained the 1931 Ford coupe from, that I was considering building my own chassis, he did not think that was possible. I told him that I thought it would be relatively easy to do once I know what suspension I wanted to use.
For the last 34 years I have been acquiring all kinds of tools, mostly, wood working equipment. Many times, I thought it was cheaper to buy the tool than to buy something pre-made. I made our first coffee table because we could not afford to buy one in the early days. Over the years made a fan back Windsor rocking chair, a Deacon’s bench, and all kinds of elaborate wooden toys from circus trucks to a complete train set. Renovations on our various homes over the years were big on the list. To have somebody else perform renovations in our house was out if the question. I bought the tools and opted to do the work myself. Remember, the library, it’s a fantastic resource to learn just about anything. This is the story of my life, learning how to do something, just because I could not afford to pay someone else to do it. This starts to become a problem. Knowing how to do so many things makes you reluctant to have people work for you. This is starting to change now, only because there is only so much time in the day and you cannot do everything yourself. The other issue is that not everything deserves equal billing. Some things are more worth while to do yourself and other times it is a lot simpler to leave it to the people who make their living doing a certain job. I have even progressed to the point I get our new car serviced, including the oil changed by the dealer on a regular basis. That’s an incredible step for me.
Finally, after a considerable amount of time researching suspension and chassis designs for street rods, I came to the conclusion that I would use a C4 Corvette suspension for the front and back of the car. Now, I need to find the suspension parts.
Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 2
After a considerable amount of thought and research, looking at commercial front and rear suspension components I made a decision. I felt that a more interesting route for my project would be to use C4 Corvette suspension components. Part of me always looks to do something just a bit different, and I always look for a challenge. Besides, I do not ever remember seeing a C4 Corvette suspension on the front of a Model “A” street rod. I am not saying it hasn’t been done, just that if it has, it is not very common. Many bigger street rods use the front suspension from a Corvette, and countless number of street rods, including Model “A” Fords uses the rear suspension.
1986 C4 Corvette Indy Pace Car convertible bought on eBay and used as a donour car for the hot rod project. This has everything you need, front & back suspension, drivetrain, steering column, etc...
The C4 Corvette uses a very well designed and good looking aluminum independent suspension on their cars. Aluminum is light and can be nicely polished to a brilliant shine. This is perfect for an open wheel street rod. The hub width between the brake rotors and using Corvette style/type of rims provides a prefect match to the Model “A” Ford body. Below are a few specifications of a 1986 C4 Corvette.
- wheelbase: 96.2”
- front track width: 59.6”
- rear track width: 60.4”
- ground clearance: 4.7”
- convertible weight: 3266 lbs
- front/rear weight distribution: 50.2%/49.8%
The frame for the Model “A” Ford will need to be modified. It will need to be narrowed in the rear and slightly widened in the front. These changes will accommodate the C4 Corvette suspension components. I will talk in more detail about this later on.
1986 C4 Corvette Indy Pace Car convertible - rear view - it doen`t have to look pretty, just have all of the parts you want in tack.
Now the search for the suspension components from a C4 Corvette has started. A check at the local wrecking yards did not produce anything. Then I started looking on the internet, more specifically, eBay. I started bidding on a few complete units from the front and back of a Corvette separately. There was a bit of a problem. Shipping these items is expensive, especially from the United States. These items are bulky and heavy. Most of the items I found were too far away to pick up myself. The search started to seem hopeless. Then I came up with the idea of purchasing a complete car. This started to make more sense very quickly. Some of the front suspension units had a finally selling price on eBay between $500 and almost $1000. The rear units sold for less. Add in shipping, and I would have been paying well over $2000 for the suspension components. This included having them shipped to the door. Some would say, not bad, since many of the commercial front suspension units start at $1500 and go up from there, depending on options, and how much chrome you would like. Of course you still need something for the rear of the car.
1986 C4 Corvette Indy Pace Car convertible - engine compartment - a good engine for my application, but the TPI injection will be replaced with a standard 4 barrel carburator.
My search now changed to looking for a complete car. This would give me the suspension, a motor, transmission and lots of little bits and pieces required to build a street rod. I found a car in New York not to far from the Niagara Falls Ontario border crossing. This was perfect for me, since I was only 3 ½ hours away. I have never paid the asking price for anything I have ever bought and the dealer would not budge on the price of $3700. I could have even driven the car home. In hind site, this would have been okay and will need to explain this later on. Shortly afterwards, I found a wrecked 1986 Corvette convertible in Sterling Heights Michigan at a salvage yard and was only an 1 ½ hour away from my home. The car was hit on the rear driver’s side of the car. I bought the car for $2000. Now I had to arrange to get it home. A friend of mine had a pickup truck and we rented a U-Haul car trailer. If I had bought the car in New York, I could have driven the car home and made my life my simpler.
I made a few phone calls to the Canadian and American Customs departments to make sure about the procedure with importing a vehicle into Canada. The Customs officials I talked to were extremely helpful. This was a very important step to ensure a stress free border crossing. Everything was all set, and away we went to pick up the car. The only problem I had was at the salvage yard I purchased the car from. They wanted to transfer the title of ownership to my name in the State of Michigan. I explained this was not necessary but they insisted on it. So I left with the car and a freshly printed Michigan title for a 1986 Corvette convertible. I even needed to pay their state taxes on the transaction. Again, something I did not count on and was not required to do. Oh well. Importing a car into Canada did not seem too difficult. In fact I have been across many times and had more difficulty crossing back into Canada with a car load of electronic equipment I purchased at an amateur radio flea market in Ohio.
The car was unloaded from the trailer. This is when I discovered that the driver’s side rear half shaft in the rear end was sheared in the wheel hub. This was a result of the accident. Again, I started wishing I purchased the Corvette in New York. In the end, I paid almost $3500 to get the wrecked car into the driveway. This included the price of the car, foreign exchange, Michigan State taxes, taxes at the Canadian border, the rental of the trailer, gas money, and a bit of cash for my friend’s time. The New York car would have only been slightly more to get home with less transportation hassles and I would not need to search for the broken rear end parts. Everything is a lesson in life.
We parked the car and started checking things over. It has almost everything I needed to build a street rod. The next challenge was to dismantle the car and dispose of everything I did not need. That will be the next part of the story and my hot rod build alone with the initial concept of a new frame for the Model “A” Ford using the Corvette suspension components.
Come back next week to read more about the Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod and continue with part 3.
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