Not much experience with these other than riding in a couple of F 6's powered by the sweet sounding, run like a sewing machine flattie when I was a kid.

If you like a pressurized flat, here are some pics I found looking for something in the supercharger forums:

Flathead Ford, Hudson Hornet 7X, flathead supercharger kits & vintage nostalgia racing

If this is old news, my apologies.... (well, of course it's old news...but you know what I mean)