Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Entrant | Chassis | Engine | Points |
| --- | --- | --- | --- | --- |
| 1953.0 | Rennkollektiv EMW | EMW | EMW Straight-6 | 0.0 |
| 1957.0 | Dr Ing F Porsche KG | Porsche 550RS (F2) | Porsche Flat-4 | 0.0 |
| 1958.0 | Dr Ing F Porsche KG | Porsche RSK (F2) | Porsche Flat-4 | 0.0 |
| 1960.0 | Dr Ing F Porsche KG | Porsche 718 (F2) | Porsche Flat-4 | 0.0 |
| 1961.0 | Porsche System Engineering | Porsche 718 | Porsche Flat-4 | 0.0 |
| 1964.0 | Rob Walker Racing Team | Cooper T66 | Climax V8 | 0.0 |
Question:
What chassis did the porsche flat-4 use before 1958?
Answer:
Porsche 550RS (F2)