I wonder who are the two drivers?

Chryslers placed 3rd and 4th in 1928, behind the winning Bentley and the runner-up Stutz DV32. Here's an excerpt from a story about the 1928 race, by Pete Hagenbuch in Allpar, the Chrysler historical website:

"The Chrysler racing team consisted of four 1928 Series 72 roadsters, powered by L-head inline six cylinder engines with cast iron blocks and cylinder heads. Bore and stroke was 3.5” x 5” and each displaced 248.9 cubic inches (4.1 liters). Compression ratio was 6.1:1. The roadsters weighed in at 3005 pounds with a wheelbase of 118.75.” The Chryslers were all painted in a light cream color with black fenders and trim. Drivers were European, with circuit experience being a primary consideration; Car 7 had the brothers Ghica and Cantacuzino, Car 8 had Stoffel and Rossignol, and the other cars had Lepori, Chiron, and Benoist. The latter two were well-known Formula 1 drivers."

In 1929 a Chrysler 75 driven by Stoffel and R.Benoist finished 6th, just ahead of the Chrysler 77 of De Vere and Mongin who placed 7th.

Very similar, if not identical, to the Chryslers entered in the 24-hour Grand Prix d'Endurance at Le Mans in 1928. Two of four finished, placing third and fourth behind a 4.5 liter Bentley (1) and a Stutz (2). If this is one of them, then it is in street clothes, for the race cars had abbreviated front fenders and were painted a primrose yellow.

Not a bad showing for a marque barely four years old, and an American one at that!