At the Monterey Historics, I had the pleasure of meeting David Kinney, one of the most obsessed high ranking auto appraisers in the business. He also writes and is associated with Keith Martin of Sports Car Market. While there are many guidebooks published on values, none compare to the 3 issues per year book that David publishes.
He is way into the minutia of models and for example, disects The C O B R A in the following ways by serial number
260 W&S
289 W&S
289 R&P
427 Street w 427
427 Street W 428
427 Comp
427 S/C
Daytona Coupe
COB
COX
MK IV
Completion Cars
CSX 4000 Series Glass and Alloy
***If you love cars and follow their values from A-Z, this is a must.
www.carsthatmatter.com
$40 for 3 issues per year and internet access or $20 per issue is a bargain any way you slice it. You won't believe the in depth coverage.