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2013-14 Shelby GT500
CNC Ported Heads on high 700rwhp Combo
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<blockquote data-quote="Catmonkey" data-source="post: 16043786" data-attributes="member: 124025"><p>Except that the intake flow results are not quite that impressive. Here's graph that Slawco has on their port work for a GT500 head on the intake, which includes a competition valve job. For typical mild cam profiles, (.450" to .500") you might see 20 cfm on the intake at peak valve lift, but the exhaust is in the right range. It might be worth 25-35 horsepower on pump, which makes it a pretty expensive mod for the gain. And it will get much better results with more octane, which wasn't in the initial post.</p><p></p><p>What the graph doesn't show is how much of the increase in flow is from the port work vs. the valve job. IMO the increase in flow rates at lower valve lifts are attributable to the valve job. I'll admit Fox Lake has higher number on their website, but there is no indication of the pressure drop for the readings. I've been there, done that, so I know the price tag on one of these builds. I put my money in springs and chain drive components that can run more aggressive lobe ramp profiles within the range of duration for a streetable pump gas grind than you'll find in NSR grinds. Sure you can do both, but once you're looking at the estimated cost, you might want to draw that line in the sand somewhere. And like I said, if you have an unlimited budget, go for it. </p><p></p><p>OP, 4cc will be about a 1/2 point of compression on a 5.8. The stock combustion chamber could use some blending.</p><p></p><p>[ATTACH=full]1525686[/ATTACH]</p></blockquote><p></p>
[QUOTE="Catmonkey, post: 16043786, member: 124025"] Except that the intake flow results are not quite that impressive. Here's graph that Slawco has on their port work for a GT500 head on the intake, which includes a competition valve job. For typical mild cam profiles, (.450" to .500") you might see 20 cfm on the intake at peak valve lift, but the exhaust is in the right range. It might be worth 25-35 horsepower on pump, which makes it a pretty expensive mod for the gain. And it will get much better results with more octane, which wasn't in the initial post. What the graph doesn't show is how much of the increase in flow is from the port work vs. the valve job. IMO the increase in flow rates at lower valve lifts are attributable to the valve job. I'll admit Fox Lake has higher number on their website, but there is no indication of the pressure drop for the readings. I've been there, done that, so I know the price tag on one of these builds. I put my money in springs and chain drive components that can run more aggressive lobe ramp profiles within the range of duration for a streetable pump gas grind than you'll find in NSR grinds. Sure you can do both, but once you're looking at the estimated cost, you might want to draw that line in the sand somewhere. And like I said, if you have an unlimited budget, go for it. OP, 4cc will be about a 1/2 point of compression on a 5.8. The stock combustion chamber could use some blending. [ATTACH=full]1525686[/ATTACH] [/QUOTE]
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2013-14 Shelby GT500
CNC Ported Heads on high 700rwhp Combo
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