let into the fenders and, on later models, two additional grilles fitted to the hood. During road testing the new Chrysler engines began to fail. After investigating it became apparent that the cause of these problems was that these engines were not designed to run for extended duration at the speeds possible on the continent. Lawrence returned to the States looking for the resources to remedy these problems. The engines destined for use in Monicas would all be specially tuned by Racer Brown in the United States. Modifications to the engines included a Racer Brown stage 3 road camshaft with hydraulic lifters, an Edelbrock Torquer intake manifold, a 4-barrel Holly R6909 750 CFM carburetor, a Chrysler marine specification oil pump, Clevite shell bearings, Forge True pistons, Marine specification valves, and a Felpro race-quality gasket set. The compression ratio was 10.5:1. All of these changes combined to bring output to @5400 rpm and @4000 rpm. It is reported that some cars may have been built with the larger 5.9 litre (5898 cc) "360" version of the Chrysler LA engine. These cars would have been designated Monica 590s. The dimensions attributed to this version by various sources differ, sometimes significantly, from those of the 560 model. In particular the 590 is listed as being 630mm shorter with a 100mm shorter wheelbase and 140 kg heavier. It was also more powerful, the engine being rated at and . The revised and renamed Monica 560 made its world premier at the Geneva Auto Show in March 1973. It would appear again at the Paris Auto Show in October. The car was priced at 164,000 francs (roughly US$34,000 at the time), at a time when a Rolls-Royce Silver Shadow cost 165,000 francs. After the Geneva show Tastevin invited several racing drivers and automotive journalists to Paul Ricard's circuit, Le Castellet, to evaluate the new Chrysler-powered car. Among those there was driver/journalist Paul Frère, whom Tastevin invited to "lend a hand" in sorting out the car's handling. He would also be the person who wrote the semi-official obituary for the Monica car. A rapid succession of prototypes would be built to finalize the car. The cars at Le Castellet were numbers 8 and 9. Numbers 10 and 11 were built for crash-testing and numbers 12, 13 and 14 came after. Prototype 14 was basically pre-production and would eventually be one of the cars Tastevin kept for