I have what I need. The diagrams are in the catalogs, and I did not look at others, but found it in an old Eckler's catalog. Speakers are 6 X 9.
Boatman

FYI - Not all 6x9 speakers are the same. The newer ones come with a "center" cone that makes them very hard to install with the original speaker covers. I had to order new ones(wanted to save the orig.) and cut some of the grill work out to make room for the speakers. If your replacing the speakers try to take the old ones/orig. with you to compare the depth.

Save the Wave

Depth is fine on these new ones. GM Delco, 8 ohm. They are 6" round, and have the dust covers. I have now found brand new 6 X 9 - 10 ohm speakers, so I will use them instead, as they will bolt up perfect to the brackets. I took out 4 ohm speakers and an aftermarket radio. I installed a NOS 79 GM Delco AMFM stereo radio in this 79. Kstyer told me that I need 8 or 10 ohm speakers for that radio, just like the original. Thanks for the tip.
Boatman