When it absolutely positively has to run on pump gas....... along with the fact that it’ll probably never go to the drag strip again........ is it really worth pushing the CR envelope?

How much power do you really think you’re leaving on the table if the compression is 10:1 instead of 10.5:1?

And then there’s the question of 93 octane pump gas.
It’s not available everywhere.
Who’s to say how long it will remain available in your area?

I’d shoot for about 10:1, and put in a cam that makes more sense with how you’re using that car.

For a 505, something like an Icon 842 piston set up at zero deck, along with a set of 75-78cc heads puts you right in the sweet spot.