Fuel tank replacement

It looks like I need to replace my diesel tank. I would much prefer to install a small bladder or plastic tank, but understand that would be lighter and most likely not OD compliant. Is that correct?

If I were to epoxy lead equivalent in weight to the additional weight needed, in the area of the original tank, would that be allowed per OD rules? Same question if I decided to go with a smaller aluminum tank.

Thanks.

The class measurer will comment on this, but have you considered retaining the old tank and putting the new bladder tank inside of it? You could cut open the top and take out the baffles / trim sharp edges and lay the bladder in the old tank. You could plumb the new hoses and the tank will be "protected" if you screw the cover back on the old tank with corner brackets. That way you would retain the weight, but rely on the bladder for holding fuel.

You'll lose the ability to have a float level sensor with the bladder tank.