Chevrolet Performance has quietly closed the book on one of its most celebrated crate engines, officially discontinuing the LS9 Long Block — the supercharged small block that powered the C6 Corvette ZR1 and became a legend among engine swap builders.
The LS9 now appears on Chevrolet Performance’s site with a simple label: discontinued. For enthusiasts, it marks the end of a factory engineered package known for swallowing boost, surviving abuse, and delivering exotic car power with small block simplicity.
Born from the ZR1 program, the LS9 was built around a 6.2 liter Gen IV small block with a forged rotating assembly, titanium connecting rods, and a cast aluminum block reinforced with six bolt, cross bolted mains. Rated at 638 horsepower and 604 lb ft of torque, it became a go to choice for high end restomods and forced induction builds.
Its hardware included:
• Forged steel crankshaft
• Titanium rods
• Forged aluminum pistons
• L92 style aluminum heads with 68cc chambers
• Titanium intake valves and sodium filled exhaust valves
With a 4.065 inch bore, 3.622 inch stroke, and healthy valve lift (.562/.558), the LS9 was engineered to live at high rpm and under high boost — a rare combination in a factory crate engine.
With the LS9 gone, Chevrolet Performance is steering customers toward the LSX376 B15, a crate engine designed specifically for supercharged and turbocharged builds. Its forged internals are rated for up to 15 psi of boost, and its baseline output — 473 hp and 444 lb ft naturally aspirated — leaves plenty of room for builders to push harder.
The B15 ships without an intake manifold or accessories, giving tuners freedom to tailor the induction setup to their preferred forced induction system. Chevrolet notes that its published power numbers come from NA testing; boosted output will vary depending on the setup.
Just as the LS9 exits the stage, Chevrolet Performance is teasing what appears to be its next act. Earlier this month, the brand posted a tightly cropped photo of a black, textured intake manifold with the caption: “Something BIG is coming.”
The image shows surrounding hoses, clamps, and connectors — hints that this isn’t a concept piece but a production ready component. The proportions suggest a modern pushrod V8, aligning with GM’s ongoing investment in its Gen 6 Small Block family.
The teaser has already fueled speculation that GM may be preparing to unveil a new large displacement variant, potentially related to the recently announced 6.7 liter LS6 slated for the upcoming C8 Corvette Grand Sport. The intake design could signal airflow improvements, packaging changes, or thermal upgrades aimed at supporting higher output.
Whatever GM is preparing, the message is clear: while the LS9 era has ended, the small block story is far from over.
Source:
Chevrolet Performance
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Had to happen sooner or later. LS6 is rated at 535 / 520. So barely 100 less hp (and 85 less torque) than the LS9. And with far less complexity.
There’s a boosted engine on the horizon for the Gen VI. Likely a supercharged one. And the old is making way for the new.
A turbo from the ZR1 would be much nicer, and should be an easy adaption, with lots of torque, and minimal parasitic loss.