What the heck are these brackets????

[jlmerie]

A buddy and I just got back from looking at a 1972 Cheyenne Custom Camper truck for sale. It is a very nice and very original truck, around 74,000 miles. Everything looks right from front to back. SPID matches truck and options. It is a small block truck and when looking under the hood we saw something we could not explain. I don't know wether to call them brackets or what. Oh each side of the engine bolted to the frame rail above where the motor mounts would be were these brackets. I took some pictures and am attaching them. These look like they have been there a long time. What the heck are these brackets????