Call Angela Burnett at Heacock Classics---one of the major classic insurers.
Tel: 1-800-678-5173. I got "agreed value" for full purchase price of car. Also have my 86 Plus 4 insured thru them. Go direct not via your agent who may only have his "target" list. (Read higher commission) No reason to use a middleman.

About 40% less than the quote from Hagerty. Believe Chubb also quote similar, just a little higher.

Good luck.

Tom S