West Australian Council


The intent of these classes are to keep costs affordable but maintain competitive racing.  Persons who wish to compete in these classes should keep within the spirit of the class.  Competitors are not to participate in any actions or proposed rule changes that may escalate the costs of this class (unless related to safety issues). 


All boats must comply with current APBA Displacement regulations/rules except engine specifications as laid out below.

  1. Engine to be a recognised production engine not exceeding 6,000 cc (366ci) cast iron block and heads.  Original stroke and bore, rods and length free.  Head to be engine manufacturers port, valve position and angles (i.e. Chevrolet 23 degree).  Valves may be aftermarket one piece stainless. NO lightweight values (i.e. titanium).  Springs, retainers and locks free.  Rocker valve train free (no offsets).
  2. Rotating assemblies to manufacturer’s specifications.  Aftermarket are acceptable however NO super lightweight types permitted.  Material may be removed to balance engine rotating assembly.  Pistons to be flat top.  Weight to be within manufacturer’s   specifications.
  3. Camshafts free.  Roller lifter cams permitted.
  4. Distributor free however it must accept a rev limiter and show to be limited to 7,200rpm (7,000+).  This must not be able to be altered during racing.  Rev limiters to be fitted on all current motors prior to the 2008/9 season.
  5. Manifold to be a single inlet commercially manufactured item, NOT custom fabricated. Plenum height including spacer, wedge or gaskets not to exceed 182cm from top of block.
  6. Carburettor 750cfm.  NO machining permitted, commercially available.  Maximum of four venturi’s.  Documentation to substantiate cfm.
  7. Fuel premium unleaded pump.  NO exotic aftermarket fuels or additives permitted.
  8. Oil system free.  Dry sump permitted.
  9. Exhaust free but must meet noise requirements and WA State Rules (i.e. water in pipes and not exceeding 92 decibels @ 50mts).
  10. Gearbox, shafts and propellers as per APBA rules.  No stern or surface drives (Proposed National rule change  “No stern drives in restricted displacements?  To be    voted on at the National AGM in August – current Rule 102.5 allows stern drives).
  11. Hulls to meet current APBA displacement rules.
  12. Forced induction not permitted.
  13. No external cam adjustments permitted.
  14. All new generation aluminium engines (i.e. LS2) would require rev limits and/or weight penalty to be decided by the Class.

August 2007


  1. Stock LS1 5.7lt Commodore Engine (apart from below listings).
  2. Pump fuel (no additives).
  3. 6500 Rev limited.
  4. 650 Holley.
  5. Performer Manifold or Similar.
  6. MSD Ignition System to Suit Coil Packs.
  7. Valve Springs & Rockers Open.
  8. No Aftermarket Camshafts.
  9. Exhaust Open (must run water to exit) but must meet noise requirements and WA State Rules (i.e. water in pipes and not exceeding 92 decibels @ 50mts).
  10. Oil System Open
  11. Safety.  As per APBA displacement rules.
  12. Gearbox, shafts and propellers as per APBA rules.
  13. Hulls to meet current APBA displacement rules.

October 2014 (Revised January 2017


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