I meant bolt in factory items, so with a 308 and V8 3spd you could use a readily available V8 tailshaft and diff. If you tried to fit a Chev with the 3spd the box moves so you need a custom tailshaft plus mods to the crossmember to suit, and to legally Engineer/register a HJ with a 350 you are supposed to use the bigger rear uni as the HQ 350 powered cars did so a tonner rear diff would be required.

You could also option a 10-bolt in a HQ-WB behind a 6cyl, as a heavy duty diff. I've only ever come across one though, and only ever found evidence of a handful of others.

If you were going down the Chev route with this one you'd probably just use a TH400 anyway!