The new Type 175S Delahayes which ran in the French G.P. are those which made their first appearance at Le Mans and have 4 1/2-litre six-cylinder engines, with the normal Delahaye valve arrangement of push-rod operated overhead valves. Inlet and exhaust ports are on the off side and three Solex horizontal carburetters feed the cylinders by paired manifolds while the six exhaust ports discharge by small stubs into a single pipe. Fuel is fed from the rear tank by two mechanical pumps mounted on the near side of the engine and these are supplemented by an electric pump on the bulkhead. In front of the radiator and below it is a smaller radiator for cooling the oil. As usual a Cotal gearbox is employed and this drives to a normal rear axle. Suspension at the back is by 1/2-elliptic springs with shackles at the back and brake torque arms are fitted parallel with the springs, as are the friction shock-absorbers. The front suspension follows standard Delahaye practice of independent suspension with transverse leaf spring and wishbones, together with the familiar Delahaye radius arms. Bendix cable brakes are still retained and 5.25 by 18 front tyres were used, with 7.00 by 17 rear. The new Delahaye, while following the typical French sports car layout, has the appearance of being a very large and ungainly motor car, compared with, for instance, the 4 1/2-litre Talbots, and on the corners it added still further to this impression, compared with many of the other cars that were running. Pozzi’s car nevertheless won, at 141.844 k.p.h.
The H. W. Alta, on the other hand, which finished second, was as small and compact as any of its continental brethren. It was running more or less in the same guise as when it won the Manx Cup Race, except that for the G.P. de l’A.C.F. it was equipped with wings of light alloy, spare wheel, lights and starter, etc. For this event, four Amal carburetters replaced the more normal twin S.U.s; these were of the 10 T.T. type, each with its own float chamber. Fuel for this event was commercial, of 80 octane, so of course the compression-ratio was lower than when it was running in the I.O.M. During the closing stages of the race the Alta and the Ferrari were running only 100 yards apart and it was interesting to compare their respective abilities for cornering. Although the Alta had a tendency for its front wheels to lean away from the bend it remained remarkably steady and the Citroën rack and pinion steering gear gave a precision line and ability to hold that line without a lot of wheel-sawing, which some continental sports cars seem to require. Like most of the drivers in the race, Heath suffered from overheated feet — for the day was one of the hottest that the South of France could produce — and finished with large blisters on his heels.