I would avoid making the shackles any shorter than factory. I believe shortening them can cause some ride travel geometry problems. Great job on the front!
The tiny hole just above the leading edge of the air valve can be plugged and redrilled just BELOW the air valve to allow quicker response from the secondaries. It functions as a sort of passive "accelerator pump". Some factory carbs came this way.
I know exactly what you mean. That spring under the arm is so stiff that the splined connection doesn't stand a chance over time. I've tried to think of a way to improve that arrangement but haven't come up with anything yet. It doesn't matter much on most cars but on a second gen the hood is...
Great news! Enjoy your car. I assume the new module came with some heat sink compound to put on the base before screwing it down. It is needed for a long and happy life for the new module.
I have an idea that I want to try on my 77Z before the bumpers are repainted. I am going to use a router to put a little radius on the lower edges of both bumpers. I like the bumpers but I'm not a fan of the hard sharp edge at the bottom. I think a nice radius of just the right size would...
https://nastyz28.com/threads/another-dash-speaker-question.310297/#post-3545902. It can be done. The project has not progressed past what you see in this old post. I'm thinking about eliminating the grille in the dash center entirely to see if people notice.:)