Reducing Agreed Value

[Curtis in MA]

I was reviewing my insurance policy and notice a $20,000 agreed value.
I don't think the car is worth this. What would you estimate it at?

The car is a 1930 standard coupe without a rumble seat. Stock except for alternator, oil filter and turn signals. One fender and rear spares. Drives well. Have done a few 100+ mile trips.
Been in the family for 60+ years so no plans to ever sell it!