Picture a rectangle in your mind. If the corners are square (90 degrees) then the measurement from one corner to its opposite will equall the length of measurement from the other two corners.
Measure from specific points on the framerails to other specific points and then do the same for the other side of the car.
You can also follow the car down the road and see if it tends to sit "crab like" i.e., its front and rear tires don't line up.
5R08A, "298"(+.060, 6,000+ rpm), T-10, Crane XR-i, Disc (F), Dual Master, Heim Strut Rods - Spherical Bearing LCAs, Roller Perches, Arning Drop, 1" & 75" Anti-Sway Bars, Export & Monte Carlo, "functional" hood scoop, and GW Subframes.
Victory Red, Eagle Wheels, Power Antenna, White Int. w/ Black trim, Right & *Left* Indicators, Tach, Cruise, and a Glass Rear Window.