Posted by casebro on Sunday, September 29, 2002 at 10:43PM :
In Reply to: "performance" 230, chapter 2:planing heads posted by Ryan McNabb on Sunday, September 29, 2002 at 7:58AM :
I'd heard that they used to go to 14:1 on flatheads- the valves open into "holes" in the head, with an 'air channel' to the combustion chamber. I'd guess that whatever you can mill off the head without having to grind valve clearance would breathe o.k.
Won't you have to have a spark plug installed to check clearance w/ the clay?
Re: What a higher ratio does, is makes the burnt charge push that much harder against the piston. Half the volume= twice the pressure= twice the horse power. It will also intake better, as there will be less residual burnt gasses to dilute the fresh charge.
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