C-Notch on a 54

[Houston54]

Should have put a C-notch in during the initial build but did not so now I am correcting that oversight.

The frame is already boxed on the inside so the plan is to add a 1/8 thick gusset to the outside of the frame rails as shown. Cut out the notch and box in the notch using some 3/16 flat stock that will be bent to conform to the notch shape. The inside frame surface will also receive a 1/8 gusset plate similar to the outside plate.

The plan is to leave one inch of material from the top of the notch to the top of the frame. Is that enough? I will be running leaf springs.