Complex sentence: The origins of the Flint can be traced back to the Willys car company, which had begun work on a proposed 6-cylinder car but then had to sell off this prototype as part of its efforts to raise cash during a financial crisis.
Split into simpler sentences: The origins of the Flint can be traced back to the Willys car company, which had been working on a prototype for a proposed 6-cylinder car. Willys had to sell off this prototype as part of its efforts to raise cash during a financial crisis.