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73-87 Chevy _ GMC Trucks => Performance => Topic started by: Sartobuilt on February 05, 2013, 06:45:22 am
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I currently have a 1985 454ci. in my 1980 chevy K30 4x4. It is mechanicaly stock except for an rpm airgap intake, headers, 650 cfm holley and advanced the stock cam. I have a 850 cfm holley and some 3933148 heads that have been worked over that I have layin arround that I would like to put on.
After some investication on the heads I found these castings to be 1969 396/265hp, 366T, 427T, with either 122cc or 112cc chamber. It appears they have been milled to a 98cc. (I have not yet CC'd them myself it is writen on the gasket surface). They also have been ported and 2.19I and 1.88E valves installed.
So my main question is how much have these been milled and are they gonna give me problems with the intake manifold? In my peliminary measurements taken from the heads currently on the engine is they have been milled .030. But using -.005 = 1cc. with a 122 cc chamber you would have to take off .120", with a 112 cc chamber that would be .070".
Thanks for you help guys...
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The guy milling the heads should have stamped the total mill in the head's deck surface, and whether it was a flat mill, or angle mill.
At .030 you might get away with just bolting on the intake with just some slight port matching, but .070 is going to need you to mill the intake to get them to mate properly.
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Thanks Engineer, That is the main qustion i wanted answered. After some further measuring they have been milled .120". As much as I would like to use these heads I am not milling my intake to make it work. Not to mention new pushrods and possible piston to valve clearance issues. Im gonna pull the valves and springs junk the heads and purchase a set of good bare heads.
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Wow .120!
Those are some pretty thick decks, but with that much milling I'd be afraid of cracking them.