A flat plate bigger than the manifold on the drivers side, has the bolt holes and ports cut out. I am pulling the 260 and TH350 out my 70 S. I will take pics tomorrow. Never seen one before that recall.

 

I just took the 307 out of my Wife's 84 Riviera and it has them. They are heat shields. I have seen them on many engines over the years.

 

It seems to me there is also a slip on heat shield, thinking my 81 Delta 88 had that style. I figured being on a 260 it would be something with emissions. Either way the 260 and TH350 are out and next weekend will go in the 88.