These K frame lightening threads are rather scary IMO.

Consider these elements for consideration of just gravity loads:

a. on a TB car, all gravity forces/etc go from the tire to the TB pivot on the K frame and then back to the chassis/frame.
b. Most cars mount the single heaviest most dense item (motor) directly to the k frame, that makes for a very efficient and short load path
c. On a motor plate TB car, the gravity forces that the motor contributes has a more convoluted (less efficient/less stiff) path back to the tires and thru the K frame.
d. On an aftermarket coil spring car the tire gravity forces go thru the upper spring mount, and the motor's gravity forces find their way back to this upper spring mount by way of a motor plate or thru whatever k frame used.

Cornering loads are way more complex, but of reduced concern for 1/4 mile applications

The amount of stiffness lost due to outer flange removal/reduction, and/or ANY crossectional reduction, in ANY plane is huge, and IMO unwise for the minor weight reduction achieved to the most critical suspension structure on a TB mopar..