Direct answer
If the vehicle is registered in Western Australia, start at the WA Government page on modifying your vehicle and any vehicle-examination pages the Department of Transport links from there. VSB 14 is the national technical code. WA decides who may sign and what examination is required.
Process, not a copied list
Do not import another state’s approved-modifications list into a WA build. Open the WA page, identify whether your job is listed as not requiring prior approval, requiring an examination, or requiring an engineer. If the page is silent, ask the department. Silence is not permission.
Identity and examinations
Engine number and other description fields still sit on the register. A swap that changes them is an administrative event as well as a mechanical one. Book the examination pathway the department names, not a casual “she’ll be right” visual.
Next
State rules hub. Check with the WA Department of Transport or a person they recognise before you modify the vehicle.