Collector car insurance

After filling out the app online and submitting info and pics, got a call back from Hagerty today and was told they wouldn't cover the car because it has nitrous. Any suggestions on other companies?
Like the idea of agreed coverage and decent rate due to probably will only drive it couple hundred miles a year. Will call Grundy next, but may be same?
Go with American National (Anpac Chrome) There are a dozen or more American National Insurance offices in the Minneapolis metro area. I group my collector car insurance with my house insurance and with the refunds my old car insurance is pretty much free.