Sorry it took so long, have over 10000 pictures on photo bucket now and it takes too long to find them now.

Here's the 2 different filler necks that I know about on E bodys, identify which on you have. Most likely the one on the right for your 73.

The part number on the right in this picture fit's the filler neck on the left above. Those are Car Quest numbers, they can be crossed.

This what it looks like installed. I have been using them for close to 10 years now on both my cars, they fit and seal perfect.