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Old 09-28-2007, 02:43 PM
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What u think of 3998993 sbc heads

was just wondering what anyone thinks about these heads 3998993 (68-76)

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Old 09-28-2007, 02:45 PM
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thin, crack prone, big chambers 76-80ish
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Old 09-28-2007, 02:55 PM
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The 993 casting is a heavy casted head that came on the following:
3998993....72-73...307/350......75cc chambers
3998993....current..350.........Goodwrench crate motors,"Hecho en Mexico", 75cc chambers
They aren`t that great for performance, being they have a large chamber and a not so good intake port. These are the basic smog heads.
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Old 09-28-2007, 03:18 PM
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Originally Posted by 83chevstang
was just wondering what anyone thinks about these heads 3998993 (68-76)
There not the best heads for sure, but depending upon your budget, you can actually get some surprising results. Some time ago Chevy High Performance magazine did a Mr Goodwrench 350 build up from stone stock to screaming wild in itty bitty steps see the included URLs.



Warning! Reading beyond this point brings out the Greed for Speed!







These are also reprinted in a larger book published by CHP titled;

"Small-Block Chevy Engine Buildups: How to Build Horsepower for Maximum Street and Racing Performance"

Another really good read for the budget builder is; "How to Build Max Performance Chevy Small Blocks on a Budget"
By David Vizard

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Old 09-28-2007, 10:35 PM
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They are the best flowing of the large chamber heads along with 487s.........not that thats saying much.
If ya got um and there in good shape there OK for a mild motor.I got a set on my engine now.
As far as I researched though,I don't think they are crack prone like the 882s....but I may be wrong.
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