Which to Build - LS3 or 418
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Staging Lane
Joined: Jan 2012
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Which to Build - LS3 or 418 I need to get started on an engine for my 71 Camaro. Car will be a dedicated track car with a little street driving. I want as much power as possible but still have some reasonable durability. I am looking for a powerband of 3500-7200. I want to use the Trick Flow Gen X 255 heads. My thinking is the short stroke will be happier at this rpm but don't want to be looking for more power after the engine is built. I know the LS3 block was not designed for a 4" stroke like the LS7 but the 418 seems to be very popular. Any advice on which size engine as well as parts recommendations is appreciated.
Other specs: T56, Edelbrock single plain, 4150 TB, Holley HP ECU, rear gear tbd.
Other specs: T56, Edelbrock single plain, 4150 TB, Holley HP ECU, rear gear tbd.
418 spun to 7K will most likely be quicker than a 376 to 7500. I would go with the stroker for the added torque. Built a little milder with forged quality parts should mean a longer life too.
With the 255 heads you want a bigger cid motor then a stock LS3 as your rpm are not real high to use them up
With the durability that would be your valvetrain and camlobe selection mostly but a .866 piston pin(custom pistons) would help you if you go with the 4" or 4.125" stroke as the piston will not stick out as much
With the durability that would be your valvetrain and camlobe selection mostly but a .866 piston pin(custom pistons) would help you if you go with the 4" or 4.125" stroke as the piston will not stick out as much
Thread Starter
Staging Lane
Joined: Jan 2012
Posts: 61
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I'm a little confused by the comment. If I am correct the 255 head is actaully a smaller port than the factory LS3 head so why would it not work for 376 cubic inches?
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Launching!
Joined: Jan 2011
Posts: 274
Likes: 1
From: Collierville, TN
You could go with a 3.9" stroke or a 3.825" stroke.
4.08 x 4 = 418.369
4.08 x 3.9 = 407.910
4.08 x 3.825 = 400.066
Callies makes a 3.9 in a magnum that is a very good crank.
Just a thought....
Also, if you are going with the TFS 255 you may want to consider going to a lighter valve if you are turning high RPM for extended periods of time.
4.08 x 4 = 418.369
4.08 x 3.9 = 407.910
4.08 x 3.825 = 400.066
Callies makes a 3.9 in a magnum that is a very good crank.
Just a thought....
Also, if you are going with the TFS 255 you may want to consider going to a lighter valve if you are turning high RPM for extended periods of time.
Last edited by FLYZNTN; Dec 5, 2013 at 06:42 AM.
Thread Starter
Staging Lane
Joined: Jan 2012
Posts: 61
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