Exact Purpose of Hemispherical Heads?

Ranger Mike

trivia-Back when the " new hemi" was introduced in 1964 it was a real dog. Drag racers were very upset tha tthe engine did not perform as well as the venerable 392 CID hemi..i think it was Pete robinson or Don Garlits that wa so pi--ed off he diecide to blow the s-B up and cranked about 60 degree lead ( advance ) into it. The engine really took off..seems the factory boys were way conservative on the timing advance and this was one very high RPM engine and needed a lot of advance..once this was discovered ..nothing could touch the hemi...