Is it necessary to replace the crown wheel bolts on 8-3/4 ?

Cool.
And don't forget that this stuff is over 40 years old now.........
I hear you on the cost, the shipping and exchange rate on money can be brutal, even here in Canada!
Yeah, it's easy to get ripped on the shipping. I have bought a few things for my Mopars from Canada and shipping wasn't too bad at the time (sellers helped out). Re the bolts - I just priced some, Doctor Diff has some for A$54 (incl shipping cost by First Class) and there are some ARP ones here on Australia ebay for $76.