Good questions! I been wondering the same! The lowest part on my Cobra is 3 and 3/4" high. The
oil pan bolt (plug) is the same as the lowest part of my frame rails. I WAS lower than this! I recently raised the car a "little" by installing new front springs (boy, coil overs would be nice)! It is TO low for everyday "normal" drivng (speed bumps, etc.) but I race it and want it as low as I can get it, and STILL be able to drive to the track.
I believe my rear axle is "off set" to one side when measured from the body to the top of the tire. I HATE that! You can't "see" it (unless I point it out), but you can measure it! I THINK they aligned the exact center of the axle with the frame rails. The rear axle SHOULD be slightly OFF CENTER with the drive shaft running at a SLIGHT angle because the pinion gear is NOT the very center of the axle! Think about it, the pinion is "off" to one side on a solid rear axle (9" Ford).
I need to jack up the car and take extensive measurments to get to the bottom of WHAT is really mis-aligned here! A quick measurment indicates a perfect frame, but I DIDN'T use a plumb bob to mark EXACT centers!
Mark all four corners with a plumb bob (car jacked up), then measure front right to left rear diagnolly. EACH diagonal measurment should be the same! If not, bent frame! Your four "reference" points for EACH wheel need to be painfully accurate (taken from the FRAME, not some "moving" suspension part)! Only then can you blame the body shell.
PLEASE let me know what you found out.
Ernie