My $.02 - horrible idea. There are a ton of investments that make better financial sense. Your question, in essence, is would it be a good idea to buy a muscle car as an investment towards my retirement? The answer is NO. Max out your 401K, max out a Roth IRA, buy a house, get some mutual funds, then buy a rental property.... etc etc etc.
For example, buying Harley Davidson stock in 1982 would be a much better investment than buying a softail in 1982.
The main idea with a car is can you find a buyer. I have a 65 Tempest that I can't give away. I invested money in the car and can't find a buyer at break even price.
If you are concerned about risk look at 30 yr T bills or bonds.
The market will kill a car buyer over and over consistently.
The only time classic cars are going to pay off for you is if you make some finds. An old lady with a 56 Chevy coupe in the barn with 7,500 miles on it... a dusty but perfect 63 split window vette... basically you have to find a car that you can buy for $15K, invest $5K and sell for $25K. Original, numbers matching, original condition phones are the only thing you can look at as an investment.