340 Piston identification. Silvolite?

Thanks for all the geat info, I measured (with a Harbour Freight micrometer) they came out to 1.230 and with adding the .492 came out to 1.722, so from above if they are 8.5-1 would it be a big difference to run a better piston, also what’s the ideal for a hot street car 10.5?
Ideal is a good dynamic/effective compression aka cranking psi.