A Little More Displacement Can Go A Long Way With the LS1
There is no replacement for displacement!
383 LS1 Overview
In the hot rod world, a 383 is one of the most common displacements for Small Block Chevy strokers. It's extremely common to take a 350 block and install a stroker crank into it when you do a rebuild to gain 33 cubic inches of displacement. Similarly, you can take an LS1 block that displaces 346 cubic inches and install a stroker crank in it to create a 383 stroker. This option is not very common in the aftermarket LS market because GM created larger displacement factory engines such as the LS3 (376 ci) and LS7 (427 ci). However, if you already have an LS1 that needs a rebuild, then a 383 stroker is an awesome alternative to installing a newer GM engine into your car.
So what does the extra displacement get you? Although you will make more power, the biggest gains come from the extra torque you will make with a stroker. The torque gain is very noticeable, especially for a daily driven street car. A stroker also allows you to run a more radical camshaft while retaining the same drivability which will allow you to make more power. However, there are some downsides to a 383 stroker. Since the piston is traveling more distance during each turn of the crankshaft, the piston speed is drastically increased. Therefore, you should improve your oiling system and valvetrain components to ensure that your engine can handle the increased piston speed. Also, LS1 strokers are notorious for piston rock which can affect longevity. As long as the engine is built correctly, most strokers have been known to be extremely reliable and durable.
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Stroker Crank and Rotating Assembly
Your 383 stroker will gain its extra displacement by using a 4.00" stroker crank such as the Scat crank pictured. The Forged Scat Crank is precision machined and has lighter throws and gun drilled mains. The forged crank is ready for big power and will withstand most boosted and nitrous applications. The forged rotating assembly (pistons, crank, rods) comes pre-balanced and ready to install.
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Camshaft
The camshaft is one of the most important components when it comes to tailoring your stroker to your application. In this build, a Comp XFI XE-R cam (PN 54-448-11 and grind XER287HR) was chosen. The cam specs are 238/240 .605/.609 112 LSA which is a great mid-range cam for your stroker that would work well for an aggressive daily driver. The same cam in a stock LS1 would be much more aggressive and would be better suited for race-only applications.
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Heads
Once you have your camshaft picked out, your power potential will largely depend on the heads you choose for your build. For the LS1, the stock castings like the 241 and 243 heads are great budget options, especially when ported. However, if you are looking for ultimate power, you cannot beat an aftermarket casting such as the heads offered by Air Flow Research or Trick Flow. The heads used on this engine are the Trick Flow GenX 215 CNC competition ported heads which are proven to make excellent power and perfectly matched to a 383.
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Valvetrain
For most heads/cam LS1 setups, the stock LS1 rockers are sufficient as they are well-engineered by GM. This engine uses Ultra Pro Magnums from Comp for added security due to their solid design and upgraded trunions. When choosing a valvetrain, you must measure to make sure your pushrod length is optimal and choose the proper valve springs for your application.
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Fuel System
The fuel system demands of your 383 stroker will most likely be met with stock fuel rails and aftermarket injectors. In this build, FAST fuel rails and 46lb injectors were used due to the FAST 102mm LSXRT intake requiring LS2 fuel rails or FAST fuel rails.
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Dyno Results
As you can see, the results are impressive! The engine made over 550 horsepower and 515 lb-ft of torque which is astronomical compared to most heads/cam LS1 street builds. What is really impressive is the massive torque available at low rpm's making the stroker outperform smaller displacement engines that might make the same horsepower. Overall, the stroker is an awesome idea for someone on a budget looking to transform their LS1.
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For help with service of your car, check out the how to section of LS1Tech.com