Try Robin Berado at Perfourmance Motorsports over at Slacks Creek ... he's a great guy and does quality conversions.
www.pms.net.au
You may pay a bit but you do get your money's worth. If you're on a budget, you can try Anthony Kellam based in Capalaba ... haven't met him b4 but he's the other person recommended for conversions.
Don't have his details but you can get them from the twincam16 forums.