need to know how to look for a real abody 4 speed car

Okay,

Thank you to all. I am looking for rear boxes but have never seen the fronts? does anyone have a picture of those?
If the car was a manual 3 speed car ( a lot of 318 Demons were 3 speed manual) it would have the hump and the Z-bar bracket.
Heck even the /6 cars manual had all of that, but this guy "feels" legit to my spidey senses. I just had never actually torn apart a 340 4 speed car before and I've striped aALOT of A-bodies in my day.
I never paid attention to the vin numbers stamped into the car either- Trunk drain rail by the quarter and the radiator support right? Is there any more I should look for?

You guys are great and thanks for the help.

On a Demon the VIN stamp won't be on the trunk gutter, it'll be on the package tray. You can usually see it by looking up at the bottom of the package tray from the trunk. Now, whether or not you can read it while looking at the backside of the stamping upside down from the trunk is another story. Maybe take a pencil rubbing to transfer it.

All of your points are valid, the fender tag, buildsheet, and the stamp on the transmission itself will be the only ways to confirm it was originally a 4 speed car. The rest of the stuff would either overlap with original manual transmission cars, or be easy to change out. That's why I generally don't buy cars based on what they were originally, it's hard to confirm a lot of that stuff unless you're going to get under the car and check the stampings. Well, that and the one's that people care about being original are usually of my price range.

If you've torn apart a lot of A-bodies, you know the more important things to look for. Does the stuff your worried about "look" factory? Anybody that can weld half decent can swap anything they want onto or off of these cars, VIN stampings included. Making things look factory is a lot harder. That's why I don't like the over-restored rotisserie jobs as a buyer. If everything is painted, it's impossible to tell if anything is original. If you look at the bottom of the package tray and see the factory overspray, the usual spots were the car didn't get dipped and have flash rusted etc, it's a lot easier to tell if it left the factory that way. If everything is uniformly painted with nice fresh paint good luck! Of course, if you're building it's nice to have all that stuff painted, knowing it isn't going to rust for a looong time.

I had to go check the Swinger for front boxes last night and they are there.
It's hard to imagine they do much just being kinda tacked in there....
Should I weld a solid seam to improve effectiveness ?

The whole car is just tacked together...:)