Ported 5.3 heads and CR
11-13-2007, 12:05 PM
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Ported 5.3 heads and CR
I had some 5.3 heads ported and milled .030 and I am getting ready to install them. What CR am I looking at with OEM gaskets. Is there thin gaskets for a small bore like the 5.3, I thin it' a 3.9x? I want to get 10.5:1. How can I achieve that?
11-14-2007, 09:05 PM
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I'm have this formula that I seen on a head info page mabey it'll help you out somehow.
Simple milling math:
You have a stock 66cc chamber and you want to get down to 63cc.
66-63=3. You have removed 3cc's
.007x3=.021 So to get your chamber down to 63cc, you have to mill the head .021
You can do the reverse, say you want to mill a head .030 to figure out how many cc's that removes you take .030/.007=4.28. Milling a stock 5.7 head .030 puts the chamber at 62 cc.
Now you will have to input your own info in there and see if that helps.
Simple milling math:
You have a stock 66cc chamber and you want to get down to 63cc.
66-63=3. You have removed 3cc's
.007x3=.021 So to get your chamber down to 63cc, you have to mill the head .021
You can do the reverse, say you want to mill a head .030 to figure out how many cc's that removes you take .030/.007=4.28. Milling a stock 5.7 head .030 puts the chamber at 62 cc.
Now you will have to input your own info in there and see if that helps.
11-17-2007, 01:15 AM
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Because I know .030 on a stock gasket is safe, but I want to know who has done more and what set up worked (example, lift mill and or gasket) I think from common knowledge if they go with more lift or the same pushrod problems may arise. You can measure, but there is valve float issues. So is .030 the max on a 5.3 head on a truck?
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11-18-2007, 07:48 AM
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Because I know .030 on a stock gasket is safe, but I want to know who has done more and what set up worked (example, lift mill and or gasket) I think from common knowledge if they go with more lift or the same pushrod problems may arise. You can measure, but there is valve float issues. So is .030 the max on a 5.3 head on a truck?
You are asking questions about compression ratios and PTV clearances after you milled the heads. Just seems like those question should have been asked before milling. And yes, .030 milling is common.
11-18-2007, 05:22 PM
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stock 5.3 heads are 62ccs. not 66. stock LS1 heads are 66ccs. mill them .030 and you will be near 59ccs. with a .040 think and 4.0" bore gasket, you will be at 11.54:1 static compression.....which is alot on pump gas in a heavy truck.
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