ross replied:

There is often a used long range tank for sale in the local classifieds for a 60.
A Long Ranger tank would be the best buy. New they cost about $800 or so.
The best ones are the ones where you just plug and play

Kev M (QLD Bound) replied:

Look Here on Trading post

This one is on the Trading post.

Cheers Kev

Gerhardp1 replied:

If the standard 90 litre tank plus the 45 litre sub tank would be enough fuel capacity, you could try a gas conversion place - they usually have a pile of the originals out the back which were removed for the conversion in the first place.

Could be pretty cheap, too. A friend with a 60 series on dual fuel (gas tank inside car) had a fuel leak the first time he filled it with petrol. I suggested he go to a gas place, since they know what the tank fittings are, and hence where it was leaking.

They thought it might be a rusted top, and were going to drop it out and replace with one from out the back - $150 cash quoted.

It turned out to be a fractured hose which they replaced - all for $70.