The winning formula forCorp.'s entirely new LS1 OHV V-8: It's the most horse-power that can be had for less than $40,000. By a long stretch.
The GM V-8 price-to-horsepower ratio is legendary, though. What makes the LS1 different is that although it's tied genetically to Ed Cole's original 1955 small-block V-8 - the bore centers are the same hallmark 4.4 ins. (11 cm) apart and its valvetrain continues to be activated by pushrods - the LS1 is most convincingly redesigned for a new millennium.
Start with basic construction, now fully of alloy. The LS1's new aluminum block, at 108 lbs. (49 kg), is a substantial 48% lighter than the iron-block of the LT1/LT4 V-8 it replaces. You'll find bottom-end durability enhancers such as a deep-skirt block, five cross-bolted, powder-metal main bearing caps, powder-metal connecting rods and a cast-iron crankshaft.
At the top end, engineers optimized the two-valve-per-cylinder design by aligning all the major valvetrain components in a single plane. John Juriga, GM Powertrain's lead engineer for the LS1, says this configuration reduces valvegear stress and, coincidentally, allowed his team to specify lighter weight, smaller pushrods and valve stems which - combined with pistons, shaved by 3.5 oz. (100 grams) - have been no small help in extending the LS1's usable rpm range.
The LS1 inlet and exhaust ports are now all symmetrical; The old 5.7L V-8 was sort of notorious for cylinder-to-cylinder flow variations. It's all topped by GM's first composite intake manifold for an OHV
V-8. The new manifold also incorporates the engine's fully electronic throttle, an item that vastly enhances the interface with traction control and stability control functions. There's no physical connection between your right foot and the LS1, and it works gorgeously.
Yes, the LS1 still employs what most regard as an antiquated valvetrain design, but considering what the LS1 is all about - propelling the Corvette - Ward's editors found it immensely more rewarding when compared with most competing overhead- cam V-8s. After all, tire-trashing torque is what you want in a world-class sports/GT car, and the LS1 delivers - RIGHT NOW - when overhead cammers are still spooling up. That such torque and horsepower comes with more refinement than one has a right to expect from nearly six liters of thumping V-8 proves how effectively the old small-block has been redesigned.
Don't think the LS1 is just for the 'Vette, either. All the great work on the LS1's innards will be carried over for iron-block versions powering GM's new range of 1999 full-size pickups and the sport/utility vehicles that will be derived from the new GMT-800 pickup platform.