This may be old news, but I didn’t know it. Even though the motor has “HEMI” plastered on it, the engine itself isn’t a “Hemi.” Curious they’d use the branding on it.
“While the heat-treated A356 aluminum cylinder heads do not have hemispherical combustion chambers, they do carry huge 54.3-mm (2.14-inch) intake valves and 42.0-mm (1.65-inch) exhaust valves. Both have hollow stems to save weight; the exhaust stems are sodium-filled to dispense with excess heat.”
From: http://blog.caranddriver.com/ten-shades-of-hell-10-things-we-learned-about-the-stonking-707-hp-hellcat-v-8/
