4103 missing part of Aluminum frame?

[busfan]

Just noticed today that I should have two aluminum longitudinal braces right back of the front end assembly.
At least if the 3207 and 3610 design are very similar? I'm using a 3207/3610 manual pub 1948 and this is a 51'  4103.

Galley way, skin and rubbub bottom do not look up to the task of support; just back of the axle.

Previous owner must have taken them out to redo linkages brakes etc, as they are like new.

Assume it changed hand's again and the braces got scrapped / lost.

On the cheap I'm thinking of welding up some tube steel and backing plates for a roll cage type design in that compartment.

Probably a good time to check the front to back alignment track?
What do y'all suggest? 

Any box aluminum recovery available at truck yards?

Cut up a truck tool chest with a torch and affix!?