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Silverado 4.3 Liter Vortec Lu3 Swap For 350sb

Mgrand21

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Mgrand21 New Member

Mgrand21

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Has anyone here swapped a 4.3 out for a 5.7 350SB? I keep reading how they are basically the same engine and my Silverado looks like it definitely has the room. I have seen enough rebuilt 350's and trannys on-line to know I can get both in great shape for $2500, will the rest of the swap nickel and dime me to death? Any info would be great, thanks

tbhuge Enthusiast

tbhuge

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The 4.3 Block is basically a 350 block with 2 cylinders cut off of it. Bore and Stroke are the same, bolt patterns for the transmission are the same. The engine came out in 1978 mostly for boat racing. Very good torque with decrease in overall weight compared to the 350. You will have to change your motor mounts and exhaust and possibly your cooling. As far as the rest of the drivetrain, that is up to you and your right foot. If you are putting a built 350 into your truck, then yes you could mate it up to everything, but it will only be a matter of time before you start finding the weekest link and breaking stuff. If you are putting a mild 350 in there and only getting on it every now and then and mostly using it for a driver, then you would be fine with the stock drivetrain. So you do have some options and control over how much you spend with this swap. And yes size wise, the 350 will definitely fit under the hood with room to spare.

 

Actually I just looked at your original post, and is this going in your 2011 truck or an older truck?? If you are thinking about your brand new truck, I would say don't do it. Sell the truck and get the engine you want. They did not make the 350 for the 2011s and you will not pass emission testing and you will void any factory warranty. What vehicle are you looking at swapping this into??

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