11-24-17:

Some grinding in the valley of the Teksid block is needed to fit the lower intake manifold from an 03 Cobra.  The knock sensor bosses need to be ground down to clear the lower intake and there are three small tabs on either side of the valley that need to be ground down for clearance as well.

Here are the before pictures:

The PCV fitting on the bottom of the intake manifold also interferes with the intake manifold, so I had to remove it.  I measured it and it will clear the valley of the block if I can screw the fitting into the pipe threads in the bottom of the intake far enough.  I could not find my RTV tonight so that will have to wait.

With a Dremel tool and diamond impregnated fiberglass cutoff wheels, I cut off the tops of the knock sensor bosses:

Next I learned that the three tabs on each side were interfering, so I ground them down.  You can see one of the end ones after it was ground down to clear here:

After the knock sensor bosses and the tabs were all ground down, the intake manifold fits great.  I figure if it clears with no gaskets, it will clear no problem with gaskets.

Here are the ground down spots:

Since I don't want any stress risers that could cause the block to fail, I smoothed and deburred the work I just did with a sanding drum in the Dremel tool.  I also deburred the casting flash that ran across the valley near each end.  I also rounded the sharp edges throughout the valley: