Adam, Quaddys are easy to find on Ebay and are cheap to overhaul. $75-$100 will get you one on Ebay and $250 to overhaul.

http://www.ebay.com.au/itm/ROCHESTER...item27c7252ea7

http://www.ebay.com.au/itm/Rochester...item2c657a51dc

Or buy a recoed carby for $320

http://www.ebay.com.au/itm/QUADRAJET...item519f59dbc8