A-body chassis dynamics, handling

I've actually made the decision to do the deal. I'm going to convert my 67 Cuda into a vintage road race car. I do have a fair amount of road race experience, but mostly in other vintage European cars.

There are many different issues I see with the A body cars to make them handle. On a basic level we need to make the chassis stiff, so that we isolate the suspension and it's ability to work.

To do that, I am planning on sub frame connectors and a full roll cage, tying in the suspension points.

Then it's about reinforcing the suspension pieces. There seems to be a fair amount written on the upper and lower a-arms and how weak they are. Seems like you can plate the lowers and buy tubular uppers (if you get he uppers, get the double adjustable ones, so you can adjust camber and caster. (I need to figure out how to make the uppers look vintage.....) The front suspension uses Torsion bars, which act just like a spring. The shock dampens the osculations. On a race car you can (if you have adjustable shocks) modify the compression speed (downward action of the shock) and rebound (upward speed). This is very important as it can really effect the way the car handles.

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Remember when a car is traveling/racing, there are 4 contact patches that are each the size of a sneaker. The car weighs 3000lbs, so for sake of argument say 750lbs per wheel. As the car rolls from one side to the other when turning, and combined with front to rear weight transfer (braking or accelerating), you can move a lot of weight around the car and ultimately put too much weight on one wheel/tire, compared to it's ability to stick to the ground. You utilize your driving skill and the suspension to manage this effect, as ideally you want equal amount of weight on each tire at all times. That's where skill and suspension setup come into play. The job of the driver is to manage the weight transfer to make sure you don't overload the car. This is an over simplification, as we could write for years about it, but hopefully just a basic picture. If you want more details on handling and it's effects there are many books. There is a great basic flip book by Carroll Smith called "engineer in your pocket" that covers cause and effect. fun easy read.

(Back to point)

So your car bobs up and down uncontrollably, so you know the T bars are "springing" the car up and down, but the shocks are not controlling it. So Start with new shocks. Don't forget to check you tire pressure, as the air in your tires are also a spring too.

You may know that Carrol Shelby moved the upper a-arms in the Shelby Mustangs and that changed the path the wheel moved on and made a dramatic difference in the handling of the cars. I need to find someone who had down work on A bodies to see if we have to move the "pick-up" points around to get the same advantages.

It is also important to make sure that the suspension mounting points are secure (tight) and all busings are in good shape, as that can also effect how the suspension moves. Also check your front wheel bearings (jack up the car, grab the wheel at 9:00 and 3:00 and/or 12/6 and see if there is any play. There should only be about 1/32ths. Also these cars are renown for bad Idler arms and pinion arms. again, check for play and replace if necessary.

This is just a glancing blow at many issues here, but I hope it's a good start!

Good luck