mm wrote:
OT An interest in hemi engines stirred me, and I found this site

http://auto.howstuffworks.com/hemi1.htm

which gave as the advantage of the hemi that 2 valves could be placed
opposite each other, instead of next to each other, and thus could be
made bigger, for more power.

I had assumed that the advantage was with fewer corners, etc. in the
combustion chamber, there was less chance of power-losing knocking.

OTOH, now it occurs to me that if the combustion chamber is domed, it
might be bigger than one with a flat top, leading to a lower
compression ratio and less power.

So why are hemi engines powerful?


The pistons are domed to match the head

see
http://www.streetrodderweb.com/tech/.../photo_09.html