CHEVROLET LS (ALL)

BMP LS Series Chevy Aluminum Block 

Although an incredible replacement LS series block for the week end warrior, The BMP LS block is simply the strongest on the market! It is cast from A357-T6 aluminum, far stronger than the commonly used 356 aluminum. The BMP block has important improvements that even factory race blocks don’t have. This translates into engine builders being able to obtain more power and enjoy improved reliability with BMP LS based engines.

Let’s start at the bottom end. Main caps made of 1045 alloy steel billet are employed. This material is tougher than the 1020 steel used by others. The caps are located by ring dowels and secured with 200,000 psi tensile strength ARP main studs. It’s important to note that the BMP LS uses a priority main oiling system, which feeds the crankshaft first and the top-end last. Others feed the top-end first and can starve the main bearings. Water jackets are redesigned to provide more support around the cylinder – important for big boost applications.

Bill Mitchell Products also recognized that in order for engine builders who employ power adders to maintain high combustion pressures with complete reliability it was essential to improve the sealing of the LS. With this in mind BMP’s engineering team added provisions for the optional use of two extra head studs per cylinder. They are designed to work in concert with any 4 or 6 bolt LS style cylinder heads. These extra bolts are not required and standard four bolt heads will fit. The six bolt pattern is compatible the GM LSX 6 bolt pattern. 

Another way that BMP has improved upon the quality of its LS block is through the machining process (which is to QS9000 standards). All BMP LS blocks are CNC machined in only two fixturing positions, which prevents the problems that can occur with production line blocks that are machined in multiple operations and the tolerances stack from one machine to the next. Bottom line, The BMP LS block is the most advanced, precision made block on the market for LS applications!

We are currently in the middle of some foundry updates and at the same time decided to use the down time  to upgrade the tooling to improve the casting quality. Projected ship dates to begin in late 2018.

TECHNICAL SPECS:

  • Material:  357-T6 aircraft aluminum alloy
  • Deck Heights: 9.240 or 9.800"
  • Deck Thickness: .600" minimum deck thickness
  • Cam Bearings: Stock
  • Can be machined up to 60mm
  • Cam Location: Stock
  • Lifter Bores: STD .843"
  • Bore Sizes: 3.990" and 4.115" rough bore
  • Bore Spacing: Stock 4.400"
  • Max Bore size 4.165", sleeve OD 4.285"
  • Sleeves: Replaceable centrifugally cast ductile iron 
  • Main Caps: Billet 1045 steel
  • Main Cap Design: All 5 Caps are 4 Bolt Design w/ all 5 caps side bolted as well.
  • Main Cap Locators: Stock registers and ring dowels at center studs
  • Main Cap Hardware: ARP stud kit
  • Rear Main Seal: STD LS one piece
  • Crank Clearance: 9.240"/4.000", 9.800"/4.500"
  • Lubrication: Priority Mains(feeds crankshaft first and then the top end)
  • Oil Systems: Can accommodate dry sump(scavenge at rear)
  • Motor Mounts: LS1 and early small block Chevy
  • Head Studs: STD GM LSX ARP Stud kits (4 or 6 bolts designs)
  • Components:  Accommodates all standard GM LS-series
  • Weight: Approximately  130 lbs. with sleeves

MORE INFORMATION:
Instruction Sheet  PDF - Adobe Reader Required