Unless you've been living under a rock, we're sure you've heard about GM's LS series of engines. When first introduced back in the late '90s, these all-aluminum mills set the Chevy performance world on end and since then it's only gotten better. The 346-inch LS1 begat the 364-cube LS2, which later gave way to the LS3, which displaces 374 ci. The growth spurt came to an end, at least for now, with the 427ci LS7. Sure there were/are other LS-based engines out there stuffed in many of GM's offerings, but none exceed the displacement of the LS7 developed for the Corvette Z06. But what if you want more? After all, the term "there's no replacement for displacement" is an often-bantered about cliche for a reason. The LS3 can easily be stroked to 416 cubes and even the expensive and sometimes hard to find LS7 block is ripe for a stroke. GM Performance Parts saw all this pent-up demand for big displacement small-blocks and decided to introduce an aftermarket offering: the LSX block. The iron block means that it can be bored out to 4.250 inches and it also means it's strong enough for high-compression or boosted applications. Additionally, it offers "race engine" features not found on GM production line blocks. Best of all, at about 2,200 bucks, it's typically less expensive than its hard to find LS7 cousin. For simplicity sake (or to just tick off the Mopar/Pentastar kids) we decided to build up a 440-inch LS. The 4.125-inch squared-up bore and stroke sounded perfect to us and this wouldn't be pushing the boundaries of the GMPP block, which equates to reliability. We also chose to go naturally aspirated to keep things simple and retain more cash in our pocket. But it's nice to know that the LSX block is capable of handling a little pressure down the line if we decided to go that route and bolt on a blower or add a modest shot of nitrous. GM Performance Parts LSX Bow Tie iron block (PN 19213964) offers quite a few features not found on factory LS blocks. The additional two head bolts per head, thicker deck surfaces, and billet steel main caps add tons of additional strength. Other refinements include improved bay-to-bay breathing, doweled main caps, a seventh transmission bolt hole, and a priority main oiling system.GM Performance Parts LSX Bow Tie iron block (PN 19213964) offers quite a few features not The block comes with 3.990-inch semi-finished bores that can be taken all the way out to 4.250 inches. In our case we were looking to build a 440, so Turn Key Engine Supply knocked the cylinders out to 4.125 inches.The block comes with 3.990-inch semi-finished bores that can be taken all the way out to 4 If you want the best "bang for the buck," it's hard to beat going with a stroker and this kit from Eagle Specialty Products makes building one a breeze. You get the whole rotating assembly ready to go in one package. Our kit from Eagle included a forged crank, forged H-beam rods, and forged Mahle pistons.If you want the best "bang for the buck," it's hard to beat going with a stroker and this When rotating assemblies fail, it's typically the rods that let go and given the stresses placed on connecting rods it's no wonder. These Eagle ESP H-beam 6.125-inch rods (PN 612503D2000) are built to take whatever we throw at them. The two-piece, forged, vacuum-degassed, 4340 steel construction provides strength while still weighing less than stock rods. Each rod is heat-treated, X-rayed, Magnafluxed and shot-peened to stress-relieve the metal. They also come standard with ARP 2000 rod bolts.When rotating assemblies fail, it's typically the rods that let go and given the stresses We assembled the Eagle rods to the Mahle forged pistons using the supplied wire locks. The Mahle pistons are hand-deburred and then coated with dry phosphate to protect against ring micro-welding and pin galling during initial startup. The piston skirts also feature their proprietary Grafal anti-friction coating. These particular slugs (PN LSX045125F08) have a dome volume of -8cc and weigh in at 450 grams. This should yield us a compression ratio of about 11.12:1-perfect for pump gas.We assembled the Eagle rods to the Mahle forged pistons using the supplied wire locks. The Like little soldiers, the piston/rod assemblies are ready to go into the GMPP block. Organization is the key here since the rods and pistons need to orient in a specific direction in the engine.Like little soldiers, the piston/rod assemblies are ready to go into the GMPP block. Organ When it came to choosing a camshaft, we wanted good power, but decent street manners as well. We also told Comp that we didn't mind if the engine sounded a bit snotty. What it came up with was a hydraulic cam with duration numbers (at 0.050) of 262/270, lift of 0.623 and a 113 lobe separation angle.When it came to choosing a camshaft, we wanted good power, but decent street manners as we The GMPP LSX block uses a proprietary cam retention plate, but it's really no big deal since they are nice enough to include it with the block.The GMPP LSX block uses a proprietary cam retention plate, but it's really no big deal sin With the cam in place, we prepped the block by installing the Clevite main bearings and laying on the lubricant. You can also see the LSX block's dowels for the billet caps.With the cam in place, we prepped the block by installing the Clevite main bearings and la It was then time to drop in the forged Eagle crank. We ordered this one with a 58x reluctor wheel, but Eagle can do a 24x if requested. The 4340 crank features a non-twist forging and Eagle put it though a multi-stage heat-treatment process. Like the rods, it's fully tested and shot-peened. For improved oiling, the crank was also cross-drilled and has chamfered oil holes. Other features like a 0.125-inch radius on the rod and main journals and micro-polishing are just icing on the cake.It was then time to drop in the forged Eagle crank. We ordered this one with a 58x relucto Next up we installed the crank timing chain sprocket out of the Comp kit (PN 3158KT). If this is tight, it may need to be persuaded into place, but ours installed easily.Next up we installed the crank timing chain sprocket out of the Comp kit (PN 3158KT). If t To handle our 440's oiling needs, we installed this pump from Moroso (PN 22120). Besides putting out large volumes of oil, the forward facing bolts are inset to the face. This makes running a double roller timing chain much easier since you won't need to shim out the timing cover.To handle our 440's oiling needs, we installed this pump from Moroso (PN 22120). Besides p Time for the fun part-popping in the pistons and rods. This task was made a ton easier by oiling up the cylinder walls and using an install sleeve in the appropriate size.Time for the fun part-popping in the pistons and rods. This task was made a ton easier by The LSX block came with APR main studs and the Eagle rods came with ARP bolts, so in terms of having sturdy fasteners, our rotating assembly was set.The LSX block came with APR main studs and the Eagle rods came with ARP bolts, so in terms One other nice feature of the LSX block was that GMPP had the foresight to notch the cylinder sleeves for rod bolt clearance. This was definitely a real time saver.One other nice feature of the LSX block was that GMPP had the foresight to notch the cylin 1 | 2 | » | View Full Article By Steven Rupp Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
