Thank you for that info Wilma. As always, it's very much appreciated!
Earl Haubrich was also kind enough to send me this picture (below) of his L78 4-speed tunnel last evening. Looks very original and completely unmolested. It shows the hole a couple inches ahead of the support brace which is where I thought it would be. My car didn't come with the original Nova shifter and everything in terms of the Ram Rod tunnel patch work was hastily performed.
Now that I have welded in and sealed up a metal patch, I'm waiting for this
Hurst Super Shifter to arrive from Summit before I cut the opening to match. Being that it has no offset and a straight little stick, it should be close to the original hole location but likely smaller in diameter? I'm going to clean up and paint the underside of the tunnel today and will be ready to drop the engine and trans in tomorrow. I'll cut a new hole early next week when the rest of the parts arrive.
Here's Earl's car that he sent me reference pictures of. Thanks Earl.