how to check if chassis is square

[snapetwo]

I am getting ready to install some subframe connectors in the dart.
Few friends were over this weekend and commented how the engine bay looks like it curves down to the nose, as if the body is bowed up in the middle.
How do i check for squareness in the body/chassis? and had how do i pull it straight before welding in subframe connectors? Might as well them in and make sure the car is square.

fyi, engine and tranny are not in the car yet, dunno if that may be causing the "bow"

 

[1968FormulaS340]

Take it to a body shop. Have them put it on a rack and measure it.

If it is bent (which I really doubt), you will need a frame rack to straighten it.

 

[dustinmoran91]

Check your door gaps to make sure their even, use tape measures criss cross of the engine bay, use levels on all four parts of the subframe, have it sitting on jack stands with them under the suspension so as to simulate it sitting on the ground. It would be best to have the engine and trans in to do this because it will sag the sub frame some, how much depends on your specific car and its condition. Is there anyway you could get a few hundred pounds in its place? Or temporarily drop it in?

 

[snapetwo]

Thanks for the info.
Ya, I can drop the engine and tranny in if needed. They are just on stands.