I thought it was four IN the floor
Don't want to know what an overhead camshaft is
I had heard it four on the floor, as opposed to on the tree, for the steering column. Or you could be making a joke that is going right over my head, since I don't see how in the floor would work.
An overhead camshaft is a camshaft located above the cylinder, inside the heads, it is more efficient that way. Most cars these days use them. Or if you were talking about the pun, it would probably be something difficult to do in a car.
That is a con: very limited room. Unless you have a conversion van. Then you just need to expect the police beating down your door about every child abduction.