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LS3 swap?

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Old Jun 27, 2012 | 08:12 PM
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Default LS3 swap?

Just curious if anyone has ever done one. What are the differences between an LS4 and an LS3? Just the accesories and the intake being reversed?
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Old Jun 27, 2012 | 08:59 PM
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A LOT.

I'm lazy, from Wiki.

The LS3 was introduced as the Corvette's new base engine for the 2008 model year. It produces 430 bhp (321 kW; 436 PS) at 5900 rpm and 424 lb·ft (575 N·m) at 4600 rpm without the optional Corvette exhaust and is SAE certified. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in (103 mm) creating a displacement of 6,162 cc (6.162 L; 376.0 cu in). It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551-inch (14.0 mm) lift, a 10.7:1 compression ratio, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.
The L76/L92/LS3 cylinder heads use 2.165 in (55.0 mm) intake valves, and 1.59 in (40 mm) exhaust valves. Improved manufacturing efficiency makes these heads cheaper than the outgoing LS6 heads, and severely undercuts aftermarket heads. The large valves, however, limit maximum rpm - 6000 in the L76 (with AFM), and 6600 in the LS3 (with hollow stem valves).
The LS4 is a 5,328 cc (5.328 L; 325.1 cu in) version of the Generation IV block. Though it has the same displacement as the Vortec 5300 LY5, it features an aluminum block instead of iron, and it uses the same cylinder head as the Generation III LS6 engine. The bellhousing bolt pattern differs from the rear-wheel drive blocks.
This engine is adapted for transverse front-wheel drive applications. According to GM, "The crankshaft is shortened 13 mm – 3 mm at the flywheel end and 10 mm at the accessory drive end – to reduce the length of the engine compared to the 6.0L. All accessories are driven by a single serpentine belt to save space. The water pump is mounted remotely with an elongated pump manifold that connects it to the coolant passages. Revised oil pan baffles, or windage trays, are incorporated into the LS4 to ensure that the oil sump stays loaded during high-g cornering."[6] Active Fuel Management is also used. Output of this version is 303 hp (226 kW)/300 hp on LaCrosse Super and 323 lb·ft (438 N·m).
The LS4 is used the regular LS2 block.
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Old Jun 28, 2012 | 09:36 PM
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The search function is your friend.
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Old Jul 6, 2012 | 11:46 PM
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i'm planning an LS3 and 6t75 drivetrain as soon as my stock trans blows. i hope the programming for the 6t75 is sorted soon. a 500hp 6 speed auto NA car should be plenty fast
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Old Jul 7, 2012 | 01:21 AM
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Originally Posted by V8ImpSS
i'm planning an LS3 and 6t75 drivetrain as soon as my stock trans blows. i hope the programming for the 6t75 is sorted soon. a 500hp 6 speed auto NA car should be plenty fast
I'd love to see the price tag to build the 6T75 to handle your supposed 500 HP LS3.

What happened to the bored 5.3 you were going to do?
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Old Jul 7, 2012 | 01:28 AM
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Originally Posted by LS1 Racing
I'd love to see the price tag to build the 6T75 to handle your supposed 500 HP LS3.

What happened to bored 5.3 you were going to do?
Actually, I already have a price to have a 6t75 built witha 600 horse guarantee from a buddy/customer of mine. He seemed to think the build won't be an issue at all. 500 won't be an issue for a cammed ls3 with milled heads, water meth, and a nice flowing exhaust.

I bought an ls3 long block core for $400, decided a bored out 5.3 isn't worth it especially with my ls3 find. I have a nice idea for a trick intake/ram air setup as well made possible by the rectangle port heads.
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Old Jul 7, 2012 | 01:34 AM
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Originally Posted by V8ImpSS
Actually, I already have a price to have a 6t75 built witha 600 horse guarantee from a buddy/customer of mine. He seemed to think the build won't be an issue at all. 500 won't be an issue for a cammed ls3 with milled heads, water meth, and a nice flowing exhaust.

I bought an ls3 long block core for $400, decided a bored out 5.3 isn't worth it especially with my ls3 find. I have a nice idea for a trick intake/ram air setup as well made possible by the rectangle port heads.
I don't doubt that you can easily make 500 HP from a mildly built LS3. ****, I make 440 RWHP with a junkyard 6.0 with 243 heads and a small cam.

I'm just curious about how this 6T75 will be built to handle that kind of power...Once the programming issues are solved!
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