I wouldn't worry Ron, the flathead is still here and going strong, and will be for a good time.
The elevated flathead numbers at stuff like NSRA type deals in the '90s and for a while was fashion. The flathead was fashionable for the street machine lot, the same as pro street, mini trucks, VW's, vans, you get my jist.
This did us some good, in got a bunch of flathead stuff made and or available again.
Those fashion followers are now in Chevrolet LS engined, tubular A arm, coil over sprung, multi link adjustable poly bushed everything, Holley dominator controlled EFI/ignition/transmission, huge brakes, huger wheeled (or rims as they tend to call them) rubber band tired, turbo charged 1000 hp creations. Pro touring is the key phrase right now. Or beat to **** pickups with a 4" deep pickup bed due to ridiculous frame kick up and air bag suspension, so it can " lay frame" I believe is the term for the frame Sat flat on the ground. I've even see a pickup circa 1970's that when the hood was open you can see the wheel sticking clear out of the inner fender and up into the hood space!
The flathead is doing very good away from this "scene". Look at The Race Of Gentlemen or Pendine sands Hot Rod Race's. Look at the Hot Rod deluxe type mags and so on. A lot of stuff at these events never goes to the NSRA national type events.
These observations above are not in disrespect of what folk chose to do to there vehicles, each to his own, they are just observations.
Flatheads ain't going away, they just going in an alternate path.
Martin.