i know it might be a dumb question, but what are they exactly?

 

they were the old heads used on 327's and 283's that had fuel injection. i have heard some people refer to the old "camel hump" style heads as "fuelie" heads. in case you don't know what "camel hump" is. it was the cast markings on the front of the head used to identify the head. they looked like two humps.

 

Ancient history..... we're talking the mechanical fuel injection used in the 1957-1965 Corvettes, and in some 50's Chevys.