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380k 5.3 "re"-build
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Staging Lane
Joined: Sep 2012
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380k 5.3 "re"-build So I have a 5.3 from my 2003 express van that was wrecked and I want to do a rebuild with some upgrades and drop it in my 99 Silverado that has a stock 4.8. I'm wondering other then the rebuild what kind of things should I add for a motor that needs low end torque (1000-3000 rpm) and won't likley ever see over 5k rpms?
If you plan on boring out the block go with a flat top piston. That will give you a bump in compression to the 10:1 depending on head and gasket. Some more torque for ya.
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Staging Lane
Joined: Sep 2012
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Higher then 91 octane is not really an option for me. All my local gas stations have 91 that's it. And I live in the boonies so getting higher octane requires driving 30 mins over by the local fair grounds to get up to 107.
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I'm sure he meant higher than 10:1, not higher octane. Id try to get around 10.7 or so on the compression.
Higher then 91 octane is not really an option for me. All my local gas stations have 91 that's it. And I live in the boonies so getting higher octane requires driving 30 mins over by the local fair grounds to get up to 107.
I'm sure he meant higher than 10:1, not higher octane. Id try to get around 10.7 or so on the compression.
Sorry, I can see now rereading that post was confusing. 91 pump gas will be just fine, that's all I can get out west as well. Just have the tune touched up when the project is over and you'll be just fine.
Thread Starter
Staging Lane
Joined: Sep 2012
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Oh ok. I was a bit confused there. What compression ratio is acceptable on 91 octane? And any ideas on heads? Info in post #3. Thanks guys. Hope to get the ball rolling here pretty soon. My 4.8 is getting tired at 250k and lets face it, it's a stock 4.8.
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Staging Lane
Joined: Sep 2012
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Teching In
Joined: Jan 2013
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From: northeast
So I have a 5.3 from my 2003 express van that was wrecked and I want to do a rebuild with some upgrades and drop it in my 99 Silverado that has a stock 4.8. I'm wondering other then the rebuild what kind of things should I add for a motor that needs low end torque (1000-3000 rpm) and won't likley ever see over 5k rpms?
Thread Starter
Staging Lane
Joined: Sep 2012
Posts: 53
Likes: 0
If I was just going to do a stock rebuild I would just start with a 6.0. I don't think I can do an intake swap or a "snail" (never heard that before, took me a minute) due to CA Smog crap. Thats why I was looking for minor internal mods.
Flat top pistons will not make a 5.3 with 862 heads 10:1 compression. It will be closer to 10.5:1
For what you're doing I would get a mild cam, Clean up the heads in the bowl area and proceed with a basic rebuild.
You can gain some compression by milling the heads and going with a thinner head gasket. Example go to a .040 head gasket and mill the heads to 58 cc's Will get you just a hair over 10:1
You really need to know how far the pistons are above the deck though as you don't want to tighten the quench too much.
For what you're doing I would get a mild cam, Clean up the heads in the bowl area and proceed with a basic rebuild.
You can gain some compression by milling the heads and going with a thinner head gasket. Example go to a .040 head gasket and mill the heads to 58 cc's Will get you just a hair over 10:1
You really need to know how far the pistons are above the deck though as you don't want to tighten the quench too much.