Description:

GM's aluminum LT production block has proven itself to be a strong performer.  We see this long block as being able to reliably handle to 1,200 hp.  That could not be said about its aluminum LS predecessor. We switch to an aftermarket LS block over about 750hp. This is a high-cost upgrade. 

An LT's design provides a number of other benefits over its LS predecessor. The key characteristic of an LT is direct injection.  This provides greater control over the ignition event allowing better tuning, a little more compression and more horsepower. The blocks come with piston oiling provisions making this a low-cost upgrade which we include as standard here. Because GM sells a lot of dry-sump LT vehicles, this too is a more affordable upgrade.

This LT4 long block benefits from our state-of-the-art CNC block machining which provides a level of precision and performance far beyond OE (see video below). All blocks are individually serialized on our 4-axis CNC for traceability. Our cylinder head machining of the new GM head includes both CNC porting on our 5-axis as well as CNC bowl blending and valve jobbing on our Newen CNC. The factory valves guides are replaced with premium CHE guides for much improved longevity.

We install premium Dura-Bond cam bearings and replace the OE main bolts with P1 main studs. The P1 studs are a major upgrade over the OE main bolts of unknown origin.  P1 manufactures all these studs from E190 steel alloy in their new Rogersville Missouri plant. The torque on a stud is all applied in a single direction whereas a bolt also twists.  Studs are not therefore susceptible to "unwinding" and provide greater clamping force. The net result is a more secure bottom end.

The Callies Compstar cranks we use are both forged and fully counterweighted. Having eight counterweights instead of six increases rigidity and reduces harmonics.  The net result is far less flexing of the crank which greatly enhances longevity. The forged Compstar Extreme I-beam rods with ARP rod fasteners are also a big jump up from the OE powdered metal rods. Another big jump up comes with the forged Diamond LT2K pistons. These have a 9cc dish and are intended to run either naturally aspirated or with light boost. The dry sump system features a Katech high-capacity, scavenging pump.

The valve train we use includes a BRE-custom COMP hydraulic roller cam, Johnson tie-bar lifters, Manton pushrods and a COMP trunnion upgrade. The LT4 heads retain their OE titanium intake valves and spring kit howver we replace the exhaust valves with Manley Inconel valves.

We offer two variants of this long block as follows:

• Stock stroke for 376 cubic inches (revs faster and higher)
• 4.000 inch stroke for 416 cubic inches (more horsepower NA or at same boost)

These long blocks are quick ship items.  We normally have machined blocks and other key parts in stock and ready to assemble. Call us at 815-725-2727 with any questions or to place your order. In the meanwhile, watch this supercharged CTSV put one of our LT builds through its paces.

Shop Video

CNC Honing Video

Block Machining

CNC Valve Job with Bowl Blending

5-Axis CNC Porting

Payment Types Accepted: Cash, ACH, wire transfer, others with approved credit and fees may apply.