Cheaper to Build LS1's
Just a few years ago Gen III and IV motors cost a fortune to build, but now they can be affordable. This shift is attributable to several factors. In 1997 GM first installed Gen III engines in the Corvette, and a year later it appeared in the F-body. However, the platform was too new to the marketplace, and aftermarket parts development was in its infancy. "That's all changed within a few years, as GM started using the Gen III platform in trucks, SUVs, and other cars, which helped make the engine more widely accepted. Economies of scale coupled with easy access to cores and components drove prices down significantly," Horace explains. "One of the main reasons Gen III and IV engines used to cost a fortune to build was that manufactures had to produce parts in very small volumes. As the LS engine has become more widely accepted and the volume of engines being built has gone up, costs have naturally gone down. Although a traditional small-block Chevy can still be built for less money, a comparable LS stroker will usually produce more horsepower. Therefore, the cost gap between building, say, a 650hp Mouse motor and a 650hp LS motor has become very small in recent years. With that cost gap narrowing so much and the LS engine's advantages in fuel efficiency, drivability and reliability, many enthusiast are making the switch with their new projects. In the future, we foresee the Gen IV platform continuing to evolve as the fastest-growing segment in the aftermarket."

LS Specialists
"The Gen IV engine platform is extremely diverse when it comes to applications. Currently we build engines for muscle cars, street rods, street/strip vehicles, drag cars, off-road vehicles, airboats, and powerboats. With such a diversity of applications and an engineering approach to engine design, our LS knowledgebase is far superior than it would be if we were to focus on building multiple engine platforms. This focus is what has led us to design products for our crate engines that we now sell to performance enthusiasts.

"For instance, our entire in-house cam program stemmed from the fact that no variable-valve-timing cam core existed, and no aftermarket cam manufacturer was willing to make us one, so we designed and built the cores ourselves. Now we offer a purpose-built cam line for all three GM Gen IV cam cores (three-bolt, single-bolt, and VVT). Although it hasn't been well publicized, we have been producing VVT cams for two years now. Furthermore, we have designed many other products simply by focusing on the capabilities of every Gen IV component. We are currently releasing 12-degree LS3 cylinder heads, our own line of shaft-mount offset roller rockers, and fuel rails for LS3, L76, L99, and LS7 plastic and aluminum intake manifolds.

"Economically, since so many parts on the Gen IV platform cross over from one configuration to another, we have the ability to keep our engine manufacturing very lean. The actual machining, honing, blueprinting, and finish assembly processes are streamlined since our engine builders follow the same routine, which reduces labor costs."

Rectangle-Port Heads
The original LS1 and LS6 cylinder heads are already dinosaurs thanks to the constant influx of innovative new castings for GM. The result is a new line of cheap and plentiful factory castings available to the public that move a tremendous amount of air. Arguably the most significant development in recent years from GM are the 15-degree rectangle-port cylinder heads that were released with the L92. These heads, along with GM's LS7 castings, are rooted in the company's Corvette road racing program.

"The GM Gen IV cylinder head design has a combination of port flow and cost that has never been seen before in the automotive aftermarket. GM is placing these cylinder heads on every truck and SUV in the country, and they flow 330 cfm right out of the box," Horace explains. Even more astonishing is that these heads are available from GM Performance Parts for less than $900 fully assembled. For this reason, Mast Motorsports utilizes the L92 castings on the majority of its crate engines and has further improved its performance and power potential. "During the R&D phase, we start with an engine simulation program and look at all characteristics of the engine-including the throttle size, intake runner length, intake manifold flow, bore, stroke, exhaust runner length, and valve timing-to determine what cylinder head configuration will respond best for a given application. Then we design custom CNC port profiles that improve port velocity and airflow while improving knock resistance in the chamber. After that, we design a custom cam lobe and camshaft that is matched to the cylinder head, intake manifold, and engine displacement. From then on, it's off to the dyno for final tuning."