It's a 25 yr old Honda!  There are a few problems with trying to prove it's worth...

1 It's too old to look in the more traditional references NADA KBB, thus a reliable reference is nearly non-existent
2 $800 isn't an outrageous offer for that particular car unless yours happened to be flawless.
3 They never give you full value unless you get replacement insurance in which case you get what it cost to buy one exactly like it.  And even then they usually only pay a percentage.

I'm sorry but you probably have a snowball's chance in hell of proving a higher value.  Good Luck though

You may want to see what your county or state places it's value at for property tax assessment.  If they have such a thing where you are.

take the $800.00 and run ...it's a freakin25 year old honda...give your head a shake...what are you thinkin...I know it's your baby and your trying to swindle your insurance company out of 5g's....it's because of people like you that our rates are so freakin high.....ja

dude, its an 83 honda. i thought they were extinct. take the fucking money and be happy.
go splurge on a 10 year old honda.

1st of all Do NOT listen to the dumbass that say your car is worthless his insurance should pay the correct amount orfix the damage... after 20-25 your car can get collectors car status... believe it or not hondas are listed in Hemmings motor news now.... and Kbb does have your car value in there under classic car now you just need to know where to look...

Low retail by nada is 1250 to 1500.  They're offering trade in value that's spot on.  Just cause it's old doesn't mean it's valuable.  Especially something like this.