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Message: <blockquote data-quote="The Electrician" data-source="post: 1343709" data-attributes="member: 20817">I found this interesting article on Hotrod magazineCombustion Chamber DynamicsA cool charge may be the first step toward utilizing a higher CR, but what happens in the combustion chamber can make or break any such efforts. A prime factor here is never to loose sight of the fact that the faster the charge can be burned the higher the compression the cylinder will stand. Chamber cavities between the piston and the cylinder head between about .060-inch - .0120-inch appear most likely to be the site of detonation. Speeding up combustion mixture motion/agitation is vital. This means maximizing the quench action. On a small-block Chevy with a stock block height, a stock compression height piston is typically .025-inch down the bore. With a .040-inch gasket this makes the static quench clearance .065-inch, which is way too wide. By cutting the quench clearance the burn rate and quality improve to the point where the motor gains compression and is less likely to detonate even at the higher ratio involved.So how closely can the pistons approach the head face? Although it comes under the heading of "don't do this at home" I have run the static piston/head clearance down to as little as .024-inch in a 350 with stock rods and close-fitting hypereutectic pistons. The pistons just kissed the head at about 7,000 rpm. As far as power is concerned, an associate of mine ran some tests in a nominally 450-horse 350 and found that each 10 thousandths of quench reduction was worth approximately 7hp. If you are building from scratch, make maximizing the quench your number one priority toward achieving compression and avoiding detonation.Read more: <a href="http://www.hotrod.com/events/coverage/0311em-power-squeeze/#ixzz3YEWMpAcI" target="_blank">http://www.hotrod.com/events/coverage/0311em-power-squeeze/#ixzz3YEWMpAcI</a></blockquote>