(ENGINE) Short block VR38 4.3L STEP Pro


Short block VR38 4.3L STEP Pro

A short block that includes the VR38 4.3L Capacity Upgrade kit.
It further strengthened the crankshaft and crankshaft main bearing cap for assuming the circuit driving.

・Expected use scene: Circuit
・Assumed torque: ~ 1500 N∙m

The assumed torque came from the in-house test data. We do not guarantee the use of the product without any damage.
Please note that the allowable torque may vary depending on the specifications of a vehicle, road surface conditions, driving conditions, travel distances, and so on when using the product on the actual vehicle.

  • The crank for STEP Pro changed the material to nitride steel and treated the surface with ion nitriding to improve durability by enhancing the surface hardness and hardened layer.
  • Expand the R-corner of the fillet weld in the crankpin to improve the torsion strength.
  • Prevents fretting by extending the crank nose 10 mm longer.
  • HKS original main stud bolt with thicker screws is used.
  • Enhance the strength by changing the material of #2 and #3 journals to Chromium-molybdenum steel.
  • Line boring for securing the roundness of the journal.
  • The main bearing and connecting rod bearing are highly selected through various tests.
  • The crank damper pulley (provided) developed only for VR43 engines reduces torsion vibrations.
  • HKS crank damper pulley only for VR4.3L
    (Cooperatively developed with ATI PERFORMANCE PRODUCTS)

  • Expand the R-corner of the fillet weld in the crankpin to improve the torsional rigidity of the crankshaft

  • Connecting rod bearing specially for VR4.3L

  • The billet crankshaft achieved reduced weight, improved response, and less torsion by using a high-efficient counterweight.

  • The bearing caps in #2 and #3 of the journal changed to Chromium-molybdenum steel to enhance the quality of the material. The line boring improved the accuracy of the roundness.


  HKS 4.3L Stock
Bore 95.5mm 95.5mm
Stroke 99.0mm 88.4mm
Compression Ratio (t=0.8) 8.6 9.0
Allowable Rotation Speed 7,400rpm 7,000rpm
Displacement 4,255cc 3,799cc


Block Modifications #2, #3 Chromium-molybdenum steel made cap
Provides the Clearance for the crank contacting section
Thicker main bearing screws
Enlarged bore and counter boring in the ladder beam bearing cap
Main bearing journal line boring
Main Bolt HKS M12 stud bolt (625+)
Piston HKS billet, Molybdenum coating
Connecting Rod HKS H-beam (Clearance for fillet weld portion)
Crankshaft Nitriding steel billet (Tungsten crankshaft weight)
Ion Plasma Nitrided
Expanded R-corner of the fillet weld in the crankpin
Extending the crank nose for attaching crank damper pulley.
Main Bearing Made by ACL
Connecting Rod Bearing Factory, fine particle peening
(WPC treatment)
Crank Pulley HKS product for VR43 only


Product Engine Capacity (ml) Type Code No. Manual Detail Remarks
SHORT BLOCK VR38 4.3L STEP Pro VR38DETT 4,255 Φ95.5 23011-AN015 Including crank damper pulley and crank keys.