You did'nt tell us what engine or tranny is in your car, but I'll try to help.
The engine CASTING # is located here...this may not match yours...395558 is a common 350 block # 396021 is a common 455 block....again this is not an excusive list........
The head CASTING number (small block) or letter (big block) is located here...
A 73 big block should have J heads or KA head casting letter. A 73 small block should have #8 heads
The VIN of the engine block is located right below the head number or letter below that freeze plug thats on the head . ( Behind the steering pump) Kinda tough to see. Driver side only, on a machined pad on the BLOCK not the head. Sorry, I don't have a picture handy now--EDIT, Ok try this picture to identify the spot--
http://i122.photobucket.com/albums/o...es/Head_ID.jpg
I can't tell you exactly where a turbo 350 trans will have the VIN, but it will be stamped on there, my guess...the drivers side.
The 400 turbo trans WILL have the VIN stamped on the drivers side on the case, just above the pan rail. It WILL be located between the selector gear (linkage) and the electrical connecter for the kick down, passing gear.
You'll need a wire brush to remove the gunk to seed the numbers. These pieces should match the last 6 digits of the VIN.