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LSX Bowtie Blocks deliver the seemingly impossible combination of professional racing level strength and entry-level affordability, the LSX Block is the next revolution in high-performance engine-building. This durable iron-block casting is based primarily on GM's production LS7 block, but designed with more material in key areas-including a thicker deck and bores-to support displacements of 500+ cubic inches or more, and unique six-bolts-per-cylinder head-clamping capability that enables forced-induction and nitrous combinations of greater than 2000 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. GM Performance Parts delivers the LSX Bowtie Block semi-finished, allowing you to finish it to your needs. Whether you're building a "tame" 500-horse street engine for your hot rod or a 1700 horsepower turbo engine for an Outlaw drag racer, the LSX Bowtie Block is the foundation for an unbeatable combination-at an unbeatable price!

Features:

100% CNC machined cast iron
True priority main oiling
6 head bolts per cylinder
Standard 4.400"" bore spacing
Extra thick siamese cylinder bores
Fully machined bores, ready to hone to fit
Semi-finished, machined decks, ready to be decked to your specs.
Increased deck thickness
LS7 style 6 bolt ""dowel located"" main bearing caps
Wet sump and dry sump cabability
Deep skirted head bolt holes (same as OEM aluminum blocks)
All stock bolt holes are stock thread size
Maintains all OEM ""LS"" family exterior mounting features
Front motor plate mounting holes added
Added material around cam bearings for extra strength
8mm exterior/interior 5th and 6th head bolt holes
All 5 cam bores machined for bearing # 12453169
Standard .842"" lifter bores
Screw-in soft plugs
Accomodated any ""LS"" series oil pand and oil pump
External oil pump feed at rear of block
Main web bay to bay breathing holes for increased HP
Access windows for cylinder head stud access (intake side)
Extra breathing pocket added near starter for better windage
Includes new cam retainer # 19166177, rear cover #19166178, lifter retainers #19166182 and OEM replacement cam bearings

Specifics:

3.880"" finished siamese bores (ready to be honed to your specifications)
9.72"" semi-finished standard deck height (ready to be decked to your specifications)
Max. 4.375"" reccomended stroke
Capable of 364 to 500 + C.I.D.
Orange powder coat finish
Accepts all Gen III & IV LS heads, cranks, cams etc.
Approximate finished weight - 225 Lbs

Engine Builder Features:

Front oil feed holes can be plugged or restricted for mechanical flat tappet or mechanical roller lifter cam applications
Can be safely machined to 9.70"" deck height
main bearing cap bolt threads can be machined for aftermarket 12mm fasteners
Maximum 4.250"" bore (at .200"" wall thickness)
6-bolt head bolt pattern (for boosted applications)
Machined for 8mm inner and outer 5th and 6th head bolts
Standard bolt holes can be machined for larger diameter lifters and/or bronze bushings
Front oil feed lines can be plugged and external oil pump and/or aftermarket dry sump oil systems can be used via oil pump feed at rear of block - may be required with certain long stroke & aluminum rod combinations
Belt cam drive systems can be accommodated (some machining will be required)
External oil pump feed at rear of block
7th transmission bolt has been added (per early SBC) stud can be installed for sanctioning body requirements
Front motor plate can be used for racing chassis applications
Threaded water plugs can be used for external heaters or coolers