[Danielg]

Good input, thank you.
Yes the frame is flush on a welding table, body bolted down, body work and gaps set accordingly.
Set it on the ground with suspension, wheels etc. it more or less sags in the middle so to speak.
I think the weak link is where the rear frame is connected to the main rails, effectively the leverage placed there weighted is flexing the frame.
Image grabbing a long paint stick and holding the end with vise grips and push down on a table, the grip point does not bend but flexes the length of the stick.
I will add a X member like I did on my old race frame, with and X to the rear frame upper cross bar.
I never imagined this car would flex this much. For kicks and giggles I see if I can set up a before and after. Engineering 101, I know it will reduce torsional twist which reduces flex but how much in the real world?