http://publicsafety.ohio.gov/links/bmv4803.pdf
QUALIFICATIONS FOR COLLECTOR’S PLATES AND APPLICATION
“Collector’s Vehicle” means any motor vehicle or agricultural tractor or traction engine of special interest having a fair market value of one hundred dollars or more, whether operable or not, that is owned, operated, collected, preserved, restored, maintained or used essentially as a collector’s item, leisure pursuit or investment, but not as the owner’s principal means of transportation.
Due to passage of supplementary legislation, additional criteria is required for the issuance of collector’s license plates. To ensure that all vehicles registered as collector vehicles are truly collectible, we now reference the National Automobile Dealers Association Classic, Collectible and Special Interest Car Appraisal Guide. If the vehicle is not listed in this guide, we do have other comparable publications that are similarly authoritative and include the 4th Edition Standard Catalog of American Cars 1946-1975 (Krause Publications) or The New Complete Book of Collectible Cars 1930-1990 (Consumer Guide). Vehicle models not listed in these publications may be considered collector vehicles if the applicant obtains documentation from the manufacturer that the vehicle was in limited production or is in demand as a collectible vehicle at the time of application. To ensure every opportunity is afforded for the applicant to be granted collector’s license plates, additional consideration will be granted to applicants providing photographs to substantiate vehicle collectibility.
found a discussion about it here, too
http://www.ls1tech.com/forums/midwestern-members/1321157-any-ohio-guys-have-collector-plates-fbody-2.html