When the L92 and the LS3 were introduced in the mid-2000s with square-port raised runners, Dart assumed that GM would remain faithful to the series and it was then they began assessing the high-performance LS market. They composed a long list of reforms but nowhere would the layout of their new LSN engine change more than in the crankcase and the lubrication system.

In the factory design the main oil gallery doubles as the lifter gallery—a multipurpose gallery that serves both the main bearings and one bank of the lifters. In fact some lifters receive lubricating oil before the main bearings. Similar to Ford 429-460 Lima engines and big-block Chryslers 383-440, this lubrication system is adequate for normal driving requirements, but almost impotent in high performance engines or highly stressed race engines. For the latter only a proper priority-mains oiling system will maintain reliability at higher engine speeds.

Though Dart’s LSN cast iron engine block has been available only since April 2013 and, now, one year later in aluminum, most knowledgeable competition engine builders are aware of the sweeping changes that have imbued it with its unique qualities.

Offered in standard deck height (9.240in) with two bore sizes, 4.000in and 4.125in., which expand to maximum bores of 4.220in (iron) and 4.165in (aluminum), the LSN will also be available in aluminum with a raised cam position within the standard deck in May 2014. Moreover a further aluminum version featuring a taller deck height of 9.900in and with raised cam will be released simultaneously.

Remarkably the LSN models with regular deck and camshaft position accommodate most stock and aftermarket components, which might be their most imaginative quality. Here in the following sequence of pictures and captions are some of its special attributes.