I see from your profile your rig is an 86. It's important to include that in your post because there are very distinct differences between the 2.6L engine in yours and the 3.0L models including the fuel system. The 2.6L has a different size/shape gas tank than the 3.0L model.

I don't believe any poly tanks are made for Montero's. You may be able to find one that fits though which would mean fabricating straps or supports to hold it in place. Alternatively you can find plenty of fuel tanks in good condition at salvage yards around the country. My 89's tank for example is completely rust free.

I recommend for an easy fix searching on car-part.com for one in a South western state that doesn't get much snow.
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