We do that in the Corvair world, but not to increase compression. We do it to make a better squish area in the head. Better squish = less pinging.

Now days, builders make compression with piston design. The heads can be left more open. Small chambers have a bad habit of shrouding the valves. You get more compression, but less flow.

If you want to build a strong street engine, stick with a 10:1 compression ratio or less. If you have good airflow and precise fuel metering, 10:1 will not ping.

The wedge-shaped chambers with the small squish area have good airflow. If you fill between the valves (to get the heart-shaped chamber) you have to step way-up on the cam to compensate for bad flow.

Build compression with the pistons (it's their job), and let the heads flow (it's their job, too)