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MTM158-124 Mast Motorsports LSX 440CID, 58X Reluctor, 12:1 Short Block

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LSX 440CID Short Block, 58X Reluctor Wheel, 12:1 Compression Ratio (based on 70cc Heads), 4.185" Bore x 4.000" Stroke

Mast Motorsports is now proud to offer expertly hand assembled LS short blocks for customers wanting a premium foundation for their engine projects. Each short block is align honed with torqued ARP main studs then decked on their CNC machine with their precision fixturing. The block is then plateau honed, deburred, and washed. Dura Bond cam bearings, ACL main bearings, and ACL rod bearings are utilized for each Mast Motorsports assembly. Using only the highest quality forged rotating assembly components from Callies, and Mahle that meets Masts strict tolerances ensure their short blocks are the highest quality available on the market. Currently LS3, LS7, and X-blocks are available from 416 to 454 cubic inches. Assemblies are available with either a 24 or 58 tooth reluctor wheel and are available with the combination of forged Callies crank and forged Callies H-Beam connecting rods. Mahle Motorsports forged pistons are also used exclusively in every Mast short block.


•Torque Plate Honed Cylinders
•True Surface Decked
•Align Honed
•Block Coolant and Oil Plugs
•Dura Bond Cam Bearings
•Callies Forged Crankshaft
•Callies Forged H-Beam Rods
•Mahle Forged Pistons
•ARP Main Studs

Note: Approximate Compression Ratio based on GM Gen IV 70cc combustion chamber!

Related Items:
LSX 440 24X Short Block
LS Oils Pans
LS Gaskets and Seals
LS Camshafts
LS Cylinder Heads
LS EFI and Carbureted Intake Manifolds
LSx Super Store

Application List


Shipping Information

  • Item Requires Shipping
  • 300.0 lbs.
  • Free Shipping!
  • FREE 48 State Truck Freight Shipping (International shipping will require freight quote)

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