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OEM 5.3L heads ???

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Old Mar 15, 2007 | 10:54 PM
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Default OEM 5.3L heads ???

I'm just finishing up on my F14 camswap and while I had the car apart I found out the previous onwer stripped the rocker bolt stud and had to helicoil it and cut the bolt shorter for it to fit. I dont doubt that the bolt will hold but its been on my mind for a while an so Im considering buying a new set of OEM heads. either the 243's which I know will also gain a few HP over the 98 heads or a set of 5.3L heads. My question is what do I have to gain by getting the 5.3L heads? I've also been told they will fit fine without any flycutting...anyone disagree?
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Old Mar 15, 2007 | 11:05 PM
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I'm assuming your running an LS1? In any event, you'll gain compression because the ports of the 5.3 are about 57cc ( I think, you should double check on the exact number, but they are smaller than LS heads). Compression should go to about 10:1, 10:5 depending on the rest of your setup. You shouldn't run into any compatibility issues though because the 5.3 is the same block as the LS1-6
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Old Mar 15, 2007 | 11:16 PM
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As far as I have found the ls1 and 5.3 heads are the exact same except for the smaller combustion chamber and smaller intake valve. If you want to use them get a valve job and put the 2.00in valves out of your ls1 heads in there. the rest is gravy.

Josh
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Old Mar 16, 2007 | 12:17 AM
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They have smaller ports that don't flow as much as LS1 heads. They're also cut for smaller valves. Not a good swap in my mind. The decrease in flow will negate the gain in compression.

Ben T.
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Old Mar 16, 2007 | 12:33 AM
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yeah thats what I wasn't sure about, I knew they would bump compression and HP from that, but wasn't sure if somthing else would cancel that out...I was leaning towards the 243's, I can probably get a few extra HP goin from my 98's to OEM 243's
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Old Mar 16, 2007 | 12:45 AM
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Yes, you could. That would be a really nice upgrade for your car.

Ben T.
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