Need to remove original black water tank offset to line up with new toilet

[hammerbambi]

I am replacing the original with a new toilet. It installs properly but
the flange hole to the original black tank is smaller than the new one which
leaves an offset in which paper and other things can hang up on. I would like
to cut this excess and make the hole larger. This material is uncuttable......
Im assuming its a black plastic but its acting more like cast iron. I was about
to resort to using a cutting torch but don't want to rush in if there is an easier solution. Used drills'/ recipricatng saw; grinders....

[Jewel65]

The original flange was cast iron and probably impossible to remove without cracking the tank. Your original tank was probably fiberglass. I would be surprised if your original tank doesn't leak. I would replace the tank with a modern poly tank. That way your new flange will screw right in. VTS has the tanks.

[PA BAMBI II]

Originally Posted by Jewel65

The original flange was cast iron and probably impossible to remove without cracking the tank. Your original tank was probably fiberglass. I would be surprised if your original tank doesn't leak. I would replace the tank with a modern poly tank. That way your new flange will screw right in. VTS has the tanks.

I am looking to install a new closet flange on which to install a new toilet...my tank is in good shape, but the mounting screws for the flange were rusted away and ground off before we had the tank re-gelled.

Can new holes be drilled/tapped into the cast iron tank fitting in order to install the modern plastic closet flange, or should I glue it in? I have access to a body shop at school and some pretty potent/strong adhesives.

Thanks in advance! Ben