Dart’s Next block crucial to LS power gains
Written by Moore Good Ink
Dart Machinery sprung a last-minute surprise at this year’s SEMA show when they revealed their LS Next block. To the racer, the transition from GM’s much-loved light, compact, street-performance block to the stronger Dart replacement promises much. Their list of upgrades is long:
|• Reduction in crank bay windage reveals significant horse power gains
• OEM holes in main webs and main caps banished as block acquires unmatched stiffness with sturdy main webs and splayed-bolt main caps
• Lengthened cylinder barrels achieved by sensible crankcase revisions. Fuller piston-to-cylinder engagement, invaluable for 4in stroke arrangements
• Priority-mains oiling introduced with provisions for wet- or dry-sump lubrication
• Deck material increased to 5/8in prevents head gaskets leaking under high boost
• Siamese cylinders add to block rigidity
• Six 7/16in head bolts per cylinder ensure adequate clamping power
• Large cam journals accommodate 60mm babbitt or 55mm roller bearings
• Constructed from cast iron or aluminum the LS Next block will become available late spring 2013
“The stock LS engine is a modern-day good engine,” commented acclaimed builder Ken Duttweiler, “but for guys wanting to make between 1,500 and 2,500hp having access to a block with a conventional bottom end will be a great improvement.”Introduced in 1996, the LS engine with its symmetrical-port heads and shallow valve angles performed well in the street-performance markets, whose enthusiasts had become attracted to it around 2005. But as engine speeds increased windage troubles in the crankcase contributed to significant power losses. According to Dart the engine lost 35hp at 6,000rpm and 70hp at 8,500rpm.
In their new design, which retains the standard LS 9.240in deck height, Dart’s solution to the windage dilemma was simple. They abolished the deep skirt arrangement at the bottom of the crankcase, replacing it with a conventional arrangement of splayed-bolt main caps secured by sturdier 7/16in bolts. The caps are available in ductile iron or steel. Dart also banished the holes in the main webs and main caps. These changes not only strengthened the lower regions of the block but also permitted the cylinder barrels to be extended by 0.375in, a bonus for long-stroke fans.
Further, Dart changed the oiling system to a priority-mains layout with cross-overs (the passages placed between the two lifter galleries) and with restrictor provisions in the valley. These restrictors are useful when high pressure or high volume oil pumps are used. They control the amount of oil that is delivered to the top of the motor.
In conclusion, this new engine block with its Siamese cylinders for added strength is available with bores of 4.000in or 4.125in and can be safely bored to 4.200in diameter. The maximum stroke is stated as 4.100in.
Dart’s LS Next block will be available in cast iron or cast aluminum. Production is planned for late spring 2013. In the meantime it can be seen at booth number 4717 at the forthcoming PRI exhibition in Orlando, Florida (Nov 29 to Dec1) and a week later at booth number 2411 at the IMIS exhibition in Indianapolis, Indiana (Dec 6 to 8).
For further information contact:
Dart Machinery, Ltd.