The LSX Bowtie Block from Eagle Chevrolet is an excellent choice for those looking to build a high-performance engine. Delivering professional racing-level strength and entry-level affordability, this durable iron-block casting is based primarily on GM’s production LS7 block, but designed with more material in key areas — including thicker deck and bores — to support displacements of 454 cubic inches or more.

Unique six-bolts-per-cylinder-head-clamping capability enables forced-induction and nitrous combinations of greater than 2,000 horsepower. Because the LSX Bowtie block is based on production LS blocks, all of the LS-Series Gen IV cylinder heads, crankshafts, oil pans, camshafts, and accessories bolt right up to it. There is also a tall-deck version for building even larger engines. Chevrolet Performance delivers the LSX Bowtie Block semi-finished, allowing you to finish it to your needs. Whether you’re building a “tame” 800 horse bracket racer engine, or a 1,700 horsepower turbo engine for an Outlaw racer, the LSX Bowtie block is the foundation for a solid combination at an affordable price.
LSX Bowtie Block specs and features include:
• CNC-machined cast-iron block
• True priority main oiling
• 6-head bolts per cylinder
• Standard 4.400″ bore spacing
• Extra-thick siamese cylinder bores
• Semi-finished, machined thicker decks
• LS7-Style, 6-bolt dowel-located billet main bearing caps
• Wet sump and dry sump oiling capability
• Production-style deep-skirt head bolt holes
• Production bolt hole and thread sizes
• Maintains production exterior accessory mounting provisions
• Front motor plate mounting holes added
• Additional material cast around cam bearings for greater strength
• 8mm exterior/interior fifth- and sixth-head bolt holes
• Standard .842″ lifter bores
• Accommodates all LS oil pumps and oil pans
• External oil pump feed (rear of block)
• Main web bay-to-bay breathing holes to support greater horsepower
• Includes unique cam retainer, rear cover and lifter retainers

For the advanced LSX competition engine builder, you will fully enjoy the following features of the new LSX Bowtie Block:
• Front oil feed holes can be plugged/restricted for mechanical flat tappet or mechanical roller lifter applications
• Can be machined safely to 9.200″ deck height
• Maximum 4.200″ bore at .145″ minimum wall thickness (naturally aspirated applications)
• Head bolt holes can be machined for 1/2″ studs
• Front oil feed lines can be plugged and external oil pump and/or aftermarket dry sump systems can be used via oil pump feed at rear of block — may be required with certain large stroke/aluminum rod combinations
• Cam bores can be machined to accept 60mm roller bearings
• Can be machined for larger diameter lifters and/or 1.060″ bronze bushings
• Belt cam drive systems can be accommodated, some machining will be required
• Front motor plate can be used for racing chassis applications (sprint car, drag racing, truck pulling, etc.)
• Threaded water plugs can be used for external heaters or coolers
• Extra stock for main bearing align-honed “
• 400 MPa tensile strength iron
For more information: https://www.chevrolet.com/performance-parts/components/engine/ls-lt-lsx-series-blocks/lsx-bowtie-blocks