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Discussion Starter #1
Ok, I have read anywhere from .530 lift to .600 lift is safe on stock 103 valve spring. Anybody here ever ran a cam with high lift on stock springs? mine is a 2012 103" and the cam has a .579 lift.
 

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The stock springs will be just fine with .579 lift. In general on a 103 engine any lift over .550 is a waste, a .550 lift will allow the engine to pull in all the AFR it can with no restriction.
 

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The stock springs will be just fine with .579 lift. In general on a 103 engine any lift over .550 is a waste, a .550 lift will allow the engine to pull in all the AFR it can with no restriction.
To clarify what Ironmark is saying, without doing headwork, more compression, bigger throttle body, etc., somewhere around 550 to 570 is all your stock engine with after market performance pipes can fully utilize.
 

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Discussion Starter #4
The heads are getting a port and polish job my a local machine shop and i plan on putting the .030 head gaskets on. Thanks guys! I really didn't want to have to spend ANOTHER few bills on springs!
 

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The port/polish shop sound be the source of that spring info, by rights.
That said, they actually go beyond .600" prior to coil bind, as we have tested them in our spring testers here, but we DO NOT suggest going there.
That spring in the OE HD head is manufactured by Comp Cams.
At .579"(?) you'll be good.
Scott
 
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