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I will check the archives for information later on but can any one tell me offhand if piston to valve clearance will be a concern in this application. 327 bored .40, resurfaced deck, .100 domed pistons, .465 lift cam, Edelbrock RPM heads, 70 cc chambers, 170 runners. I'm not sure what the piston to deck distance is. Thank you, awesome amount of great info on this site.
 

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valve clearance

When you clay the pistons to get an imprint of the valve, measure the imprint with a micrometer and you should have a minimum of .050" thickness. Anything thinner could translate to eventual valve/piston clash if your valves should happen to float.
At higher RPM your valves can actually stay open at max lift for a longer period of time as the lifter may actually come off the lobe when it hits the return side of the lobe. when this happens, thats when you could wind up with a valve coming in contact with a piston. Just be sure you have the correct tension springs for your cam and dont try over revving it; turnging it higher than the grinders recommended rpm range.
 

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Re: valve clearance

Max Keith said:
When you clay the pistons to get an imprint of the valve, measure the imprint with a micrometer and you should have a minimum of .050" thickness.
That's a little too tight. Most of the time, .100" minimum for exhaust, .080" for the intake is recommended.

However for your application, your lift, duration, and timing events tell that you will have no problems, unless you install the timing components incorrectly.

tom
 

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valve clearance

Where he to have a lot higher lift and longer duration in his cam, I would have recommended more clearance on the clay measuring. I do agree that probably .100" should be the minimum under usual circumstances.
 
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