Most, if not all states in Australia require that engine swaps be signed off by an engineer, and provide the National Code of Practice For Light Vehicle Construction and Modification (NCOP) as the guidance to follow. Some states have additional rules that the registration authorities have buried in their websites, or not published at all (for example, Victoria has a standard set of weights that often gets applied to vehicles). The arguments below are based off NCOP without reference to any additional rules an individual state may have.
NCOP can be found here:
https://www.infrastructure.gov.au/vehic ... _ncop.aspx
The part we are interested in is section LA Engine.
WARNING: NCOP is not a hard-and-fast set of rules. It is open to interpretation by each engineer. Some engineers are open to examining the rules, others are very rigid in their views. The arguments below are a good starting point, but are only here to help in the discussion with your engineer. You cannot force the engineer to accept the rules... only encourage them to view the rules your way.
Table LA1 of NCOP (bottom of Page 11) gives the recommended engine capacities. Note the use of the word "recommended"... the engineer has some choice here. NCOP does not state that engineer is limited to those values, nor can set lower ones... they are just guidance. For cars originally weighing more than 1100kg, NCOP allows:
Original mass (kg) x 5.0 = max. capacity in cc’s (for naturally aspirated cars), and
Original mass (kg) x 3.0 = max. capacity in cc’s (for turbocharged and supercharged cars).
The question then becomes: what does an FB/EK weigh? From NCOP Section 2.13.1 Vehicle Mass (page 12), the mass of the vehicle is
"the original (unmodified) tare mass of the model vehicle fitted with the largest engine available for the model in Australia but without optional accessories (air conditioning, tow bars etc.). The mass of the vehicle, whether it is a sedan, station wagon, utility, etc., should be based on the heaviest sedan version of the model (not station wagon version) sold in Australia".
We will need to convert between Tare weight and Kerb weight below. Tare weight is the weight of an empty vehicle with all of its fluids (oils, coolants) but with only 10 litres of fuel in the tank. Kerb weight is the same as Tare weight, but with a full tank of fuel.
Starting with FB Holden, the GMH publication "Holden Shop Manual "FB" Series (M32614) lists the estimated kerb weight of the heaviest sedan (FB/225) as 2494lbs (1131kg). The fuel tank capacity is listed as 9.5 imperial gallons (43.2L). To find the tare mass, we only need 10L of fuel in the car, and need to remove (43.2-10=) 33.2L of fuel from the kerb mass. Petrol density is not legislated in Australia, though typical values are 0.710-0.770 kg/L (taken from Shell information here: http://www.csinfosafe.com/CSIau/SDSIndex.aspx?flag=init). Choosing the lowest figure (0.710kg/L) means that the 33.2L of fuel weighs 23.6kg. The Tare mass of the FB thus becomes (1131-23.6) = 1107.4kg.
For EK Holdens, the GMH publication "Holden 'EK' Workshop Manual (M33099) lists the estimated kerb weight of the heaviest sedan (EK/225) as 2490lbs (1129kg). The fuel tank capacity is listed as 9.5 imperial gallons, the same as the FB. Using the same argument as the FB gives a tare mass of 1105.4kg. However, there is some leeway for the EK Holden. EK Holdens were fitted with a hydramatic transmission as an option. The hydramatic is heavier than the standard manual gearbox used in both FB and EK Holdens. Given the similarity in weights between FB and EK Holdens in the Workshop manuals, it is clear that the EK Holden weight is for a manual transmission. We can thus add some more weight to the Workshop Manual Tare mass to account for the automatic. The weight of the hydramatic gearbox is not given in the EK Holden workshop manual, but can be estimated from the Holden 'EJ' Workshop Manual (M35676) as the EJ Holden had a very similar hydramatic transmission. This Workshop Manual lists EJ Standard sedan with hydramatic as weighing 2567lb, whilst manual transmission cars weigh 2492lb (i.e. the automatic is 75lb heavier). The same weight difference applies in the values listed for Special sedans and stationwagons. We can thus add 75lb (34kg) to the EK Holden tare mass, giving an EK Holden a tare mass of (34+1105.4=) 1139.4kg.
In summary: Tare mass for FB Holden is estimated at 1107.4kg, and EK Holden 1139.4kg.
Going back to Table LA1 from NCOP:
FB Holden naturally aspirated maximum engine capacity = 1107.4 x 5 = 5537cc
FB Holden turbocharged or supercharged maximum engine capacity = 1107.4 x 3 = 3322cc
EK Holden naturally aspirated maximum engine capacity = 1139.4 x 5 = 5697cc
EK Holden turbocharged or supercharged maximum engine capacity = 1139.4 x 3 = 3418cc
Some capacities:
327 Chev at 5354cc is OK naturally aspirated in FB/EKs, but 350 Chev at 5732cc is not.
202 red motor at 3297cc is OK supercharged in FB/EKs, but the LN3 "Buick" V6 at 3791cc and the Alloytec at 3564cc are not.
Again, the argument above is not the only way to present the information to your engineer. It is presented here because the source of the information is able to be defended (e.g. uses original GMH published Tare masses). You can take information on weights from many other places. Each engineer may be more, or less accepting. There are plenty of 350 Chev EK Holdens, and blown LN3 FB Holdens out there.
Cheers,
Harv
