Available in either an RHS or Dart aluminum block, this short block is intended for naturally aspirated, pump gas applications. The RHS version includes the required custom timing cover. It is the foundation of our . This beast can drive to the track and tear it up when it gets there without breaking a sweat as you'll see in the video below.  

An aluminum block transfers heat better than its iron counterpart and weighs 100 lbs. less.  Weight reduction is a big deal for a variety of reasons.  As Newton figured out, Force = Mass x Acceleration.  The same force will accelerate (or decelerate) a lesser mass faster.  Taking 100 lbs out of the nose also shifts the center of gravity down and to the rear which greatly improves steering, braking and rear wheel traction. 

In our experience, OE aluminum blocks don't hold up well in this power range. We use both RHS and Dart blocks depending upon customer preference and availability. Both bring a six-bolt head bolt design and the strength to easily handle this power level. Both have proven their longevity in race environment. The 1967 Camaro in the photo below for example won the 2024 Road America Optima Challenge running a turbo version of this RHS short block.

We finish-machine the blocks to perfection on our 4-axis CNC mill and CNC diamond hone. This last machining step is critical as it sets the cylinder bores' final dimensions and surface finish.  Old-school manual hones can't come anywhere close to the precision and quality of our machining as you can see in the second video down below.

The rotating assembly starts with a Callies Compstar center counterweighted crank. The extra counterweights increase stiffness by 25% and reduce harmonics.  This in turn enhances longevity and virtually eliminates uneven bearing wear.  The forged Callies Compstar Extreme I-beam rods and Diamond Race Series pistons complete the standard short block.  The pistons will accommodate either LS3 or LS7 design heads. Check out the last video below to learn more about why we like center counter-weighted cranks so much. 

Two major available upgrades are a Dyer NH Series 600M rods and the Callies Apex crank.  The Dyers rods use 600M alloy which is 20% stronger than 4340 alloy.  Coupled with their double banded design, the Dyers rod offers higher strength at lower weight. The Callies Apex crank has the same design and composition as their more expensive Magnum.  The forgings are Italian with the finish machining and heat treating done at the plant that produces the Callies Compstar line. 

Have different requirements?  We offer a range of aluminum LS short blocks options to suit every need including endurance road racing, airboats drag racing and up to 70 psi boost with bilet versions.  You can also order our short blocks built out to long blocks or complete engines. Call us at 815-727-2727.  In the meanwhile, check out this beauty now powering an LS-swapped BMW in Switzerland.

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