k-member reinforcement

To check for square, measure between opposite corners and they should be the same for square. If they are very far off, the k-member is tweaked.

This.

And welding (heating) may make it out of square. Used a jig when I did mine to make sure it stayed square.

Pics on page 2 of my build thread
http://www.forabodiesonly.com/mopar/showthread.php?t=186036

-Chris