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 0.842″ 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


Our good friends at Pace Performance have passed along a memo they just received from Chevrolet Performance Parts, regarding upgrades to the LSX engine block.

You may recall that the original version of this high-performance “aftermarket” LS block is the foundation of our 388 cubic inch Procharged Project BlownZ build. The new-and-improved blocks feature three key upgrades:

  1. Added support on the deck surface
  2. G4000 iron with molybdenum – 400 mPa tensile strength, up from 250 mPa in the previous version
  3. Annulus cut within the cam bearing surface inside the block for improved oil feed location. This allows the oil feed hole to be located at the three o’clock position instead of the six o’clock position.

The improved versions of the LSX block, in addition to being offered “bare” in various bore sizes, deck heights, and states of finish, are also incorporated into Chevy Performance’s LSX376 B-8 and B-15, LSX454, and LSX454R crate engines.

The blocks are available in finished and honed standard-deck versions with either a 4.056″ or 4.185″ bore with an MSRP of $3,225.00, or as semi-finished standard (MSRP $2,775.00) or tall-deck (MSRP $3,025.00) blocks.