Absolutely. Custom tuning is 100% required. Because these engines feature upgraded cams, bored cylinders, and other upgrades, a stock ECU calibration will not work. A proper tune is needed for maximum horsepower, drivability, and engine longevity. 

Generally speaking, our engines ship fully assembled and include the block, rotating assembly, cylinder heads, valve train, factory timing cover, and a stock oil pan. Intake manifolds, fuel injectors, water pumps, and accessory drives are not included, leaving you a blank canvas to build your top-end to suit your chassis.

Powertrain Products Performance Crate Engines are available in street rod, mid-level, and full race-spec, Boost Ready® options. As such, your selected application - and any chosen optional accessories - will dictate exactly what components are included.

No problem at all. We know a lot of our customers are pulling out old carbureted small blocks to make way for modern LS power. If you do not have a rebuildable 5.3L or 6.0L core to send back to us, you simply select the option to pay the core charge upfront during checkout.

We do not ship complete engines, so this question is impossible to answer. If the engine is configured with emissions compliant components, it would likely be emissions compliant. But we make no guarantee or assurance regarding emissions compliance, and would recommend our standard remanufactured replacement engines to anyone looking for an emissions compliant engine.

Even in the performance world, we stand behind our builds. Many of our swap and Boost Ready engines come backed by an industry-leading 1-year/12k mile or 2-year/24k mile warranty against manufacturer defects (varies by specific engine level and application - view our full warranty details).

Gen III LS engines (typically 1997–2006) use a 24-tooth (24x) reluctor wheel, while Gen IV engines (2007+) use a 58-tooth (58x) wheel. Your choice depends entirely on the ECU and wiring harness you plan to run.

If you are using an older factory PCM (like an 0411 swap computer), you need 24x. If you are using a modern Gen IV computer or an aftermarket standalone system (like Holley Terminator X), you can generally specify either, but 58x offers higher resolution for tuning. We let you select your reluctor wheel at checkout so your engine matches your harness perfectly.

It depends on your intake manifold and your power goals. Cathedral port heads are phenomenal for low-end torque, throttle response, and heavier curb weights. Rectangle port heads (LS3 style) flow massive amounts of air at high RPMs, making them ideal for high-horsepower strokers like our 408 or top-end heavy boost applications.

If you already have an intake manifold, be sure to match your head choice to your intake.