After the troubled ISO team abandoned the F1 program, the IRs were modified and improved by Frank Williams, under the name of FW01 / FW02 / FW03. With Merzario and Laffite as main drivers, the Williams team faced the 1975 season on an extremely small budget. One of the FW03s was then bought by the Swiss driver Loris Kessel who in 1977 modified it calling it Apollon.