Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_181892_4 (year VARCHAR, chassis VARCHAR)
### Question:
How many years was the chassis a lotus-ford 38/7?
### Answer:
SELECT COUNT(year) FROM table_181892_4 WHERE chassis = "Lotus-Ford 38/7"