[Stretch Cab]

I also need a reference of what the chassis looks like with the engine, transmission, etc. removed, because for example, it looks like there's a "sheet metal" plate below where the engine goes that's in two pieces, and I'm wondering if it should actually be one piece.

I don't think anyone addressed this question: I think the two "Sheet metal" plates you have are the "Splash Aprons' (if I have the name right) and go to either side and below the motor. Many cars are missing these and I believe they help with the cooling when properly installed. I would be very happy to have a coupe like yours. I do have a 36 Fordor in about the same condition and am slowly getting it back together.