Insurance rates are set state by state. Too, if you have an umbrella policy, you need to check if it covers accidents in cars covered by Hagerty, Grundy, Chrome, etc. As a side note, I received my renewal last week on three cars and a motorhome and the increase for one year was $55.00! Umbrella and house insurance went up 20%. I have a one year policy that covers everything.
Thanks for posting that- that's good to know. I have two cars registered and insured (liability, not full coverage) for too much money. Nowadays, if you don't keep a car insured, DMV's going to cancel(?) your registration. I've probably wasted quite a bit of money. If I recall correctly, I used to have a policy where I could call the agency and tell them that I'm driving my backup car. And/or maybe I used to have two cars on one policy, with the second car being cheap because I could only drive one at a time.
We use Liberty Mutual for our home, auto, motorcycle and umbrella. There is no option to add vehicles pre-1981. Checked Allstate via phone and they said we wouldn't do an agreed upon value but, we do partner with Hagerty and could write a policy. Checked Geico and Progressive and no option to add pre-1981. A friend uses State Farm for three old Corvettes and his other insurance needs.