Will be changing out springs for SS units. 400HP, 9" vet, 4.30 gear DOT slick. I'm changing from /6 to 318, are the aluminum eyes worth anything, street/strip car?

When you ask about worth are you asking about performance or resale value?

They transfer forward motion a nanosecond quicker than rubber.
And transmit vibrations to the car as any solid mount has a tendency to do.
They do not break down , and that may be the biggest benefit.
Counting on those rubber bushings to break down at the same rate is optimism on a level I can't comprehend , so eventually one side will be softer than the other and steer the car in tiny , but noticeable levels.
For a performance car , I like the solid front eye bushings to be solid.

Add a greaseable bolt to help with wear...

Counting on those rubber bushings to break down at the same rate is optimism on a level I can't comprehend , so eventually one side will be softer than the other and steer the car in tiny , but noticeable levels.

This^^^

With different metals in contact, anti seize before install or something else?

anti seize is your friend. and don't be afraid to use some.