What is this frame bracket for?

[Katahdin]

Spotted this today when working in the wheel well--its above the passenger side middle axle. What attaches to it?

 

[clinto]

Your truck originally had rear exit exhaust. You will find a couple more brackets underneath if you look carefully.

EDIT:

http://www.steelsoldiers.com/deuce/16524-what.html

 

[Capt.Marion]

Your truck originally had rear exit exhaust. You will find a couple more brackets underneath if you look carefully.

Which makes sense, since your truck (I'm assuming it is the 109 in your signature) is a 1966.

 

[Katahdin]

Yep its on the 1966. I had noticed another bracket internal to the frame and suspected it was there for rear exhaust.

The external bracket seemed a bit out of place to me, but thank you for confirming what its for.