I do not have the engine-side mounts that came with the truck. I sold them with the 350 I took out of the truck, because they looked identical to the ones I had already. I took the mounts off, held them side by side, and measured alot of them, and everything was the same to the mounts I am using! So... I sold them with the block.
The frame mounts are exactly the same. I have the old ones, I can hold them up to each other, and they are identical.

So, all those other mounts you showed me probably wouldn't work, since the style that truck used to have looks the same as the ones I'm using (the rubber part was on the frame, not the block).
Right now I'm pretty convinced that it's a different bracket on the engine side. Anyone know where I can find brackets? I looked in my LMC catalog, but they only offer one kind.
Thanks.