You might want to check with RTA.
Theres still a difference between owning a vehicle with little or no ADR requirements ( e.g. seatbelts, laminated windscreens, emission controls etc ) and major engineering / structural changes to an original vehicle.
The good news is you should only need an engineers approval of the work .... not whether the work will meet ADR crap regardless of the engineering quality.
Qld transport used to have a list of approved motor transplants etc for early models .... volvos with falcon motors .... had a mate that used to surprise people at the lights on take off ... lol
I do know that RTA go by the year of the chassis ... 1966 etc can have a 2006 motor but not vice versa ... Recently looked at fitting a 1984 landcruiser with a fibreglass full body kit ... RTA still needed engineering approval ... despite the body kit having been tested, engineer approved and full qld transport approval for over 20yrs.
RTA is not there to do you any favours ....
