Bogus!!!!
Any car over 30 years can get collector registration, 1 time fee. Never register again. I've had collector plates since 2003.
Any newer cars, as long as it passes emissions (required in large cities), they don't care what you do.
I guess if you stuck 2 V8's side by side which made your car wider than 12 ft., I guess the DOT would have a problem with that.
Any police, sheriff or state patrol would love to see what's under my hood.
If they could catch me.

Australia likes to tell people what they can and cant do in regards to absolutely everything

club reg can be even more difficult than normal reg with some clubs, others not so. but you still require engineering
for engine conversions etc

New laws coming in soon, to stop any kind of street protesting so yes the Police State Australia is almost here. Club reg is the only way for now.

I just don't get this engineering crap. Why does anyone care what engine or what mods are done to what car? Doesn't Australia have anything better to do than to police people on what they can do to their own cars?
Doesn't the country have enough bridges to build to keep their engineers emoloyed?
Is this 1984?

The suspension setup (4 link with adjustable watts link) I want to run I have spoken to engineer and he wasn't keen on signing off on it. There is nothing illegal about what im doing and it is a passable modification but he basically put it in his too hard basket as the category the ar will then go in is totally different to his initial assessment.
'Go and see if another engineer will help you' after taking my money was even mentioned.
There has been many inconsistancys in the engineering (same guy) over the Datsun community with what's good and what's not.
I did discuss with him what will be on the report in regards to the r31 diff on leaf springs that's already completed and under my ute and if changing to the 4link once certified and I got a smile and said 'well yeah what happens after i do final inspection is then out of my hands' .
Il get it passed with one diff and then change it out...il be sending diff housing to engineering fabricator to get shortened and axles done soon.
(Club rego is more looking like a viable option with this car)

factory length is probably best.. but on another note why not sit down with your engineer and give ne pass ideas.. least they can tell you wahats best and whats not and whats illegal

Thanks for the feed back guys. My guards have been rolled so I most likely will go with factory length and have wheels made to suit. The intended wheel to go on are Xxr 513's its not ideal to get them now as its quite a but of money to then have sit around till project is finished.
O agree it is the best way of calculating length perfectly.
Again thanks for your input people.

Engineering still has to be within limits of the law or you still risk being defected.

Check Page 50 on my build. Gives specs. on my rearend.

Best thing get your wheels you want with the offset your after and shorten diff to suit.best way to make sure its right