All of the "agreed value" specialty car insurance companies have mileage restrictions, car garaged? who drives it, modified etc questions you will have to answer. Also they will ask how many licenced drivers and what other vehicles are in the household.
They wouldn't insure me because my wife and daughter drive 2-94 Toyotas, and my daily driver is a 99 Taurus, and I have the 05 Denali. They said that 3 of the vehicles were too old, and if one breaks down, the Viper may become a daily driver. I thought that this was BS as they are not even insuring them, only the Viper.
Try Leland West. The big 3 are Grundy, Leland West, and Haggerty