Chassis

When we first brought Donna home, she was a hot mess. On the highway, we could turn her steering wheel from 10 to 2 without much happening. If she hit a bump or pothole though she would change direction rather abruptly. Fifty years of wear-and-tear had taken a toll on Donna’s Power Steering. Donna’s steering system is actually a power assisted system where a hydraulic aid is added to a manual steering linkage. Many people replace these systems with more modern rack-and-pinion set-ups, but we will keep the power assisted system. We got in touch with Randy Meyer at Precision Products in San Antonio and sent him our components to be rebuilt. We did the following:

Donna was born with 4 wheel drum brakes. We would like a little more stopping power, so I talked to Dan at Chockostang about a front disc brake conversion. The Front Disc Brakes that came stock on the 67 Shelby’s fit on Donna’s Front Spindles. The kit Chockostang sells provides all the necessary components to convert to disc brakes that are original Ford Mustang brakes, just from a different year.

We will keep the Rear Drum Brakes (rebuilt of course) both because there is no need to increase stopping force in the rear, and because the conversion is much more complex. There just isn’t enough return on the investment. The rear drums are 10″ x 1.75″. We will get new drums, shoes, and all the mounting hardware (springs and retaining pins and such). We will also replace all the brake lines with stainless steel and get a new splitter block for the rear axle and proportioning valve for the front. Overall we intend to do the following:

When we drove Donna home it was obvious that her rear Shocks were shot. So we immediately replaced them with KYB Gas Adjust shocks. While we were at it we ordered new shocks for the front also:

Another essential component affecting ride are the Springs. Donna has leaf rear springs and coil front springs. While the rear leaf springs are likely ok, we will replace them instead of trying to clean and repaint the old ones. The front coil springs could be replaced with progressive rate springs that are purported to improve handling in the corners, but after some research we found they also lower ride height. We are very happy with Donna’s stance, so stock front coils it is. the only thing connecting the rear axel to the car are the rear leaf springs. Under hard acceleration and hard braking the rear end will attempt to move forward during acceleration and backward during braking in relation to the car body. This motion binds up the leaf springs by forcing them into an “S” shape and causes wheel hop (a loss of traction) on acceleration and stuttering (also a loss of traction) during braking. One way to remedy this is with an axel locating device, often referred to as “Traction Bars.” It just so happens that this device came standard on the 1966 Shelby GT350 and fits on Donna. Another way to improve handling is to stiffen the sub-frame. Donna is a unibody car, meaning her frame is part of the body and part of the body acts a frame. There is some flex between the front frame extension and the rear frame rails which can be reduced with Sub-Frame Connectors. Finally, by preventing the tops of the front shock towers from flexing as much you can keep the front wheels properly located and on the ground through turns. A heaver Export Brace was available on cars that were shipped overseas (probably to prevent flexing during shipment) and can be retrofitted on Donna. You can also install a Monte Carlo Bar, which is a piece of tubing that bridges the engine compartment to keep the shock towers from moving in at the top:

Donna has her original 8 inch Rear-End with 2.79 gears. With increased hp and a higher stall torque convertor we can expect Donna to be quicker off the line. It would improve her “get-up” if we increased the gear ratio in the rear end. However, we will be sacrificing highway drive-ability as the rpms will increase. A good compromise is a 3.00 Gear Ratio. We are also going to switch from an open carrier to a Limited Slip Carrier. Early Mustangs have 28 spline Rear Axles. Donna will need new bearings and seals and we are going to replace the lug studs too. We intend to do the following:

Donna has stock Ford 14 x 5 Steel Wheels with 5×4.5 PCD. 1969 was the only year the Full Wheel Covers Donna sports were available, so we are keeping those stock. She started life on 7.35×14 tires, but that designation is no longer made. The closest tire to stock is 205/75-14. After stripping and powder-coating the wheels, we will have Hankook Optimo H724, 205 /75 R14 White Wall Tires mounted and balanced.