I got my 2 classics covered under my household policy, really inexpensive.
Dude, I hope for your sake you have an "agreed value" set for those cars. Otherwise, your homeowner's policy won't give you enough to buy the tires. If you do have an agreed value, cool. I'll repeat what I always say on this subject. Every time I've talked to someone who lost a classic car insured with anyone other than a classic car insurer, they got completely hosed. "Oh, that's a really old car. It doesn't have any value. But since we've been collecting premiums from you all these years, here's a token amount."
I'm with Hagerty. I really like them. I have yet to have to file a claim, but their customer service is great, the rates are very reasonable and I even like the magazine they send me. (The latest issue has an article about Trans Am racing.)
Be aware that in order to get classic car insurance, your Mustang cannot be your daily driver and it must be garaged. If you can't check both those boxes, you're out of luck.