I think the problem is a miscommunication between you and the prospective buyers.
The price you are asking might, I say might, be reasonable if it were a 318 AC car with power brakes, power steering and even windshield washers. For a no frills, no options slanty, it's isn't, imo.
So what I think is being told to you is if it were a V8 car it might be worth your asking price.