The way most folks value their car is by studying the market: What do similar cars sell for on Hemmings and other sites? What do cars sell for at local dealers and by individiual owners in your area? Etc.
Value on the street and with an antique car dealer may not have much to do with the originality issues discussed on CRG. They should, but lots of times they don't. You also would have to have a great working relationship with a dealer to get a good appraisal. After all, they want to sell your car. I never drive my 68 when I'm going to look at cars. The dealer will spend all their time trying to get you to let them sell it.
So, that takes you to appraisers. Take a look at the site below. This is not a recommendation. I've never used them. I'm aware of them from AACA. They do have an appraiser in your state.http://www.i-van.org/
And then there is:http://www.auto-appraisers.com/
If distance is not an issue:http://www.z28camaro.com/consvcs.html
--Mr MacNeish is a CRG core member.http://www.tophatjohn.com/
There may be someone else who has actually used someone in your area, but this will get you started.