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L33 5.3l will 862 heads work?

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Old Aug 10, 2016 | 03:28 PM
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Default L33 5.3l will 862 heads work?

Hi everyone, I'm new to this site but am looking forward to all the valuable information I can get on ls motors! I am in the process of putting together a turbo motor. I have an older 5.3l ls motor out of a 99 Silverado that has 862 heads on it. I purchased an L33 short block that I want to use as a base that has the dimple rods with a good crank in it. I'm wondering if any one has input on using these 862 heads?! Thanks in advance for the input!
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Old Aug 11, 2016 | 08:53 AM
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862 and 706 are the two most common LS heads and have smaller chambers and smaller ports than stock L33 heads. You'll raise your compression ratio to ~10.5:1.
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Old Aug 11, 2016 | 12:17 PM
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What good/ affordable heads could I run to lower compression and get good flow for this L33 motor? Rightnow I just have a set of 862 heads but if there's a good affordable set of heads out there I'm willing go that route because these heads I have need to be gone through anyways.
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Old Aug 11, 2016 | 12:46 PM
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Originally Posted by JJ boost
What good/ affordable heads could I run to lower compression and get good flow for this L33 motor? Rightnow I just have a set of 862 heads but if there's a good affordable set of heads out there I'm willing go that route because these heads I have need to be gone through anyways.
317's for about $150-200
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Old Aug 11, 2016 | 12:57 PM
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The stock heads that came on the L33 work great lol. 799 or 243 castings.
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Old Aug 11, 2016 | 06:26 PM
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Originally Posted by JoeNova
The stock heads that came on the L33 work great lol. 799 or 243 castings.
OP said he bought a L33 shortblock....
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Old Aug 11, 2016 | 06:43 PM
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Originally Posted by ragtopz28
OP said he bought a L33 shortblock....
Right. And he asked which heads, so I recommended he find the heads that were on the L33 stock.

They outflow 862s by a mile and have slightly lower compression for boost.
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Old Aug 11, 2016 | 07:10 PM
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Originally Posted by JoeNova
Right. And he asked which heads, so I recommended he find the heads that were on the L33 stock.

They outflow 862s by a mile and have slightly lower compression for boost.
So are 799 and 243 heads the same? I don't have a whole bunch of knowledge about these heads. And info will be greatly approached! Thanks everyone so far on info/input i feel I'm on a good path to getting the hp I'm looking for with the right parts!
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Old Aug 11, 2016 | 07:17 PM
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Originally Posted by JJ boost
So are 799 and 243 heads the same? I don't have a whole bunch of knowledge about these heads. And info will be greatly approached! Thanks everyone so far on info/input i feel I'm on a good path to getting the hp I'm looking for with the right parts!
Yes, same head.
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Old Aug 12, 2016 | 02:21 PM
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Problem is everyone wants the 799/243 heads. Going price is usually around $400-550.

The 862/706 are cheap with 61cc chambers. Usually found for $100-150 or less.

317's are a 6.0 head and the best cheap head available IMO. Usually found for $100-200 complete. They have the 71cc chambers and the larger intake valves and ports similar (but not quite as good) as the 243. They will drop your compression around a half point on a 5.3. (.6 I seem to remember). Much cheaper to do a home port job on a set of 317’s and have them milled to your desired CC size. I picked up my last set for $120. I believe a .040 is about the max suggested mill and nets about a 64cc chamber.
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Old Aug 12, 2016 | 09:01 PM
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Originally Posted by Forcefed86
Problem is everyone wants the 799/243 heads. Going price is usually around $400-550.

The 862/706 are cheap with 61cc chambers. Usually found for $100-150 or less.

317's are a 6.0 head and the best cheap head available IMO. Usually found for $100-200 complete. They have the 71cc chambers and the larger intake valves and ports similar (but not quite as good) as the 243. They will drop your compression around a half point on a 5.3. (.6 I seem to remember). Much cheaper to do a home port job on a set of 317’s and have them milled to your desired CC size. I picked up my last set for $120. I believe a .040 is about the max suggested mill and nets about a 64cc chamber.
Thanks for all that good info! I'm going to see if I can either heads and which ever deal falls in my lap next will be on to getting them machined to a desired spec. Not too sure what that will be just yet!
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Old Aug 14, 2016 | 02:12 PM
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So I might be about to get my hands on 3 different sets of heads for cheap! I'm trying to find out which of these heads will work best for a boosted motor.. 241 , 317 ( which people already talked about) and 853? From my research the 241 heads are stock heads off an ls1 motor. And I'm unsure about the 853 heads.
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Old Aug 14, 2016 | 06:46 PM
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Originally Posted by JJ boost
So I might be about to get my hands on 3 different sets of heads for cheap! I'm trying to find out which of these heads will work best for a boosted motor.. 241 , 317 ( which people already talked about) and 853? From my research the 241 heads are stock heads off an ls1 motor. And I'm unsure about the 853 heads.
I'll say it again (of those 3)...317's for your application.
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Old Aug 14, 2016 | 07:11 PM
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Originally Posted by JJ boost
So I might be about to get my hands on 3 different sets of heads for cheap! I'm trying to find out which of these heads will work best for a boosted motor.. 241 , 317 ( which people already talked about) and 853? From my research the 241 heads are stock heads off an ls1 motor. And I'm unsure about the 853 heads.
The 241 and 853 castings are basically the same. The 317's would probably be your best option.
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