CR and pump gas question

"Look at all the aluminum headed engines out there that can't run full total timing because the CR is too high. YR says
amen to that
Just an old wives tale that an AL head can run "one more point" of compression
combustion chamber design (and splark plut location) has much more to do with it

BTW I worked on a Blown Fuel Hemi Bonneville motor- almost a flat top
and the one with just a little quench around the edge ran better than the one the didn't
However higher pressure injectors with smaller jets made more difference.
I think the Surfers were the first I saw doing this