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VR4.3L STEP Pro + short block is strengthened for stages that require even higher torque


Capable for high torque, the VR43 STEP Pro+, contains special designed I-beam con-rods which have a high buckling strength compared to the H-beam con-rods. In addition to the specifically designed crankshaft and to further enhance the torsional rigidity. The pin diameter have been enlarged, and by adopted an asymmetrical design, the cross sections between pins #5 and #6, where stress is the highest, have been reinforced.
In response to the increased weight of the pin section, the counterweight was redesigned to improve the balance ratio.


  • As with the STEP Pro, the material for the crank is made of high-end racing grade nitriding steel. Exclusively for the STEP Pro +, the crank is treated with ion nitriding, which increases surface strength and toughness that are required of high cycle performance crankshafts.
  • By increasing the inside corner radius to 3.5 and enlarging the crankpin to D57, the structural torsional strength is improved.
  • The newly developed, billet I-beam con-rods improves bucking strength by 26%.
  • The front end of the crankshaft is extended 10mm to prevent crank pulley fretting.
  • Designed specifically for the STEP Pro+, the pistons are coated with a special double layer coating, which is effective for both high-load and high-speed sliding.
  • HKS original oversize main stud bolts are used
  • Chrome Molybdenum is used to create the #2 and #3 journals to increase durability.
  • Line boring process is done to ensure the roundness of the main journal
  • The main bearing and connecting rod bearing were selected after numerous tests.
  • Crank pin diameter and inside corner radius are enlarged to increase torsional rigidity.
    (Only available for STEP Pro+)

  • Newly developed Billet I-Beam connecting rods that improves buckling strength by 26%.
    (Only available for STEP Pro+)

  • Double-layer coated lightweight billet piston made from highly hear resistant A2618 alloy (Only available for STEP Pro+).

  • Special 3D-Printed oil jets to match the I-Beam connecting rods

  • Extra-strong bearing caps for #2 and #3. Made of Chrome Molybdenum, and line boring for improved accuracy.


  HKS 4.3L Stock
Bore 95.5mm 95.5mm
Stroke 99.0mm 88.4mm
Comp. ratio(t=0.8) 8.6 9.0
Allowable RPM 7,400rpm 7,000rpm
Displacement 4,255cc 3,799cc


Block Modifications #2 and #3 Chrome Molybdenum Cap
Relief of crank interference parts
Large Main Bearing Screw
Enlarged ladder cap hole
Journal oil hole line boring
Main Bolt HKS M12 Stud Bolt (625+)
Piston HKS Billet (Double-layered molybdenum coating)
Connecting Rod STEP Pro+ Billet I-Beam
Oil Jets STEP Pro+ 3D-Printed
Crankshaft STEP Pro+ HKS Billet (Nitride steel & ion heat treatment, D57 crankpin enlarged, enlarged R fillet, extended damper mounting area)
Main Bearing ACL
Connecting Rod Bearing ACL (Width Adjusted)
Crank Pulley Original VR43 Damper

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