Chevrolet LS1 346 Engine
The Chevy LS1 346 engine was first introduced in 1997 as the motor of choice for the all new C5 Chevrolet Corvette. The engine was a huge shift in engineering for GM due to the fact that it shared very little in common (other than the typical 4.4inch bore spacing) with former Chevy small blocks. It was the first all aluminum alloy small block produced by Chevy and that was not the only big change.
The engine was given a lot of performance and durability upgrades such as greatly improved cylinder head flow as well as two 8mm cross bolts to add to the already 4 bolt main cap construction design. Another major difference is that the LS1 is free of a distributor and instead relies on the electronic control unit (ECU) to provide spark to the spark plugs through coils instead of a standard spark plug wires. The new ECU ignition system also brought a new firing order for the LS1 of 1-8-7-2-6-5-4-3 which was big change for the small block.
The changes continued with an all new intake design for the aluminum heads that were focused on performance with a 245 cfm head flow right out of the factory. This gave it a 345 horsepower output when first released which was extremely impressive at the time. With all of these changes in engineering and material design the LS1 dropped approximately 50 lbs in weight compared to previous Chevy small block engines.
In 2001 the LS1 got an additional upgrade in the redesign of the intake and exhaust manifolds which bumped the engine up another 5 horsepower and added an additional 15 lbs of foot torque. There was also a Callaway C5 Corvette built that was modified to push the LS1 up to 400 horsepower with 405 lbs of torque.
It should be noted that the LS1 was also used in the Pontiac TransAm and Chevrolet Camaro but the horsepower was decreased according to GM to the 305 to 325 horsepower range although many enthusiast claim that the real numbers were much higher.
For a complete breakdown of the full engine specs including cylinder head, valve train and cam specifications for the the LS1 be sure to check out Summit Racing
LS1 346 CI (97-00)Max Brake Horsepower: 345 hp @ 5600 rpm
Max Torque: 350 @ 4400 rpm
Firing Order: 18726543
LS1 346 CI (01-04)Max Brake Horsepower: 350 hp @ 5600 rpm
Max Torque: 365 @ 4400 rpm
Firing Order: 18726543