When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
A Flathead is a "valve in block" engine.
The valves are in the "block" next to the cylinder bore, and the valves open into part of the combustion chamber that is next to, rather than directly above, the piston.
If you look at the engine with the heads removed, you will see the top of both the intake and the exhaust valves, and the top of the piston.
If you open the hood on a car or truck with a flathead, you'll see spark plug wires coming directly out of the middle of the valve covers, rather than coming out below them.
I dont think the other two responses to your Q were answering the question you actually asked, but they might have been. A flathead V8 is a flathead (see other responses to see what a flathead is) with 8 cylinders aranged in a long V. 4 cylinders on one side, and 4 on the other.
Dang, is that what the 2 engines of mine used to look like before I scatttered 'em? I must get them to a machine shop soon!(before I forget where I put the rest of the trucks! hehehe.