Inside view
 

Inside view of the transom

Maybe its the pics but it sure looks to me like both the port and stbd corners of the bracket have pulled back from the transom. It also looks like the interior pic of the bolts is showing water weepage marks on one or two. You may want to take a real hard look at the transom to see if it is wet. I knew mine was when water dripped out after I pulled the trim tab screws - the bottom 18" was mush. I have often found leakage with lag bolts too. If there has ever been water in the transom core then it just a matter of when it turns to jello.

If the transom was recored then they may have inadvertently set a curve to it and that might explain the bracket not fitting tight.

If you have to recore or decide to replace the bracket then take a good look at a Hermco bracket - that would be my choice.

78 transom
 

You are absolutely right- both sides of the bracket have pulled out some. I am going to Remove the outboard and give it a good inspection. I will post pix of what I find.
Thanks for the advice- this site will be a huge help for getting my SC cleaned up

Has anybody found a trim tab that doesn't have such a long ram that requires cutting notches in the transom? I have a Sceptre with a bracket already installed and I'm really struggling to find a trim tab that is small enough to fit in the available space.

Interesting that the motor is mounted as high as it is on the bracket. It appears that its in the uppermost top pin holes. The bracket might could be mounted higher on the transom and not need cut outs for the tabs.

Bennett makes a short actuator that might work.