hey pumba, i've done the rollcage swap from a vh to vn. it's a littlle narrower across from pillar to pillar. i had to really stretch mine. and the bars that go to the parcel shelf i had them bent outwards ( less curve in the bend ) to suit the vn's rear window angle. if you don't rebend the back bars it wont be able to be bolted in the parcel shelf.
i hope this helps...
cheers...