Hi Wayne
Many of the hot rod or antique Chevy parts outfits carry universal tank units that should do the job. Prices in US are all over the place, but have you tried looking on something like Amazon try looking for something like this
http://www.amazon.com/Sunpro-CP7583-...ef=pd_sim_sg_8 For the fun of it I tried to search the web for sources in Australia but the web kept kicking me to US sources instead of letting me search just Australian sources.
Here are some past MLU threads on the topic
http://www.mapleleafup.net/forums/sh...ad.php?t=18818
http://www.mapleleafup.net/forums/sh...ad.php?t=16630
Back when this discussion on senders units came up Scott measured his as being 2.4 - 35 Ohms has anybody else had a chance to measure one. I'd wanted to measure mine when I had them out but my volt-ohmest unit was broken.
Cheers Phil