As per production cars apart from the following:
Chassis. Early racing chassis (LM11, LM12 and LM14) were heavily drilled on all faces of the chassis side beams and cross members. Bulkhead side castings were in Electron rather than aluminium. Lids were not fitted to the tool box. Later cars had standard undrilled chassis. The chassis numbers were located slightly back from the standard position and were stamped with larger digits. They were highlighted in white paint.
Engine. Compression ratios were raised to 9.5:1 by lowering the combustion chamber roof. Inlet and exhaust ports were polished and the inlets fitted with 1½" ‘tulip’ type valves.
Power: 85 bhp at 4750 rpm.
Torque: 100 lbft at 4750 rpm
Transmission. Many different gearboxes ratios were tried. Most had a very long first gear as a result of closer ratios between the constant mesh gears. All gears were drilled where possible and the shafts bored. Some gearbox cases were in Electron. Most works cars had a breather fitted to the front of the remote linkage housing. Different crown wheel and pinion ratios were also tried, up to 4.0:1. The crown wheels and pinions were straight cut. Ratios: 8.95:1 7.15:1 5.63:1 4.44:1
Suspension. Front and rear springs had polished leaves. Front shock absorbers were fitted with larger 112 mm diameter woods. The front axle was machined on all faces and the stub axles were also drilled. The kingpins were taper bored and the kingpin bushes were cross drilled. The front axle and steering gear were finished in polished steel.
Brakes. Brake shoes were made of Electron as were the brake back plates.
Coachwork. The standard works team car body was panelled in 18 gauge aluminium as opposed to 16 gauge for production cars. The timber frames were significantly lightened and these two factors alone reduced the overall weight of the coachwork by twenty pounds. A few cars had some ‘aerodynamic’ panels fitted behind the front shock absorbers. The works cars were fitted with a single rectangular aero screen and full width mesh screens.
The 1935 Le Mans works cars (and the privateers) had ‘Aston Martin’ painted in gold lettering highlighted in black on the bonnet side in the works pattern script. This was regarded as unauthorized advertising by the Le Mans authorities, but ultimately was allowed. In addition a union flag flying from a short flagpole was painted on each side of the car just behind the cockpit.
The 1935 Le Mans cars also had problems at scrutineering because the tyres were deemed to be sticking out slightly outside the wings. The official scrutineers insisted that strips of aluminium were riveted to the outside of the wing in order that none of the tyre could be seen. One or two later cars had these strips riveted to both sides of the wings (LM19 and the ‘Bira Ulster’) and this almost became a works ‘Ulster’ style icon.