94 V6, so it's a 4.3L S-10 blazer. It could be a central fuel injected motor or a multi-port fuel injection(10th digit Z in the vin)
Neither had an O2 sensor after the cat, so the computer does not monitor cat efficiency and doing away with the cat will not put the light on.
A clogged cat will screw with it more than no cat would, hence the poor fuel economy. I'd drop the pipe down behind the cat and poke a bar in there and break up the internals and gut it. Start it with the pipe off then and rev it to blow out all remaining pieces so it doesn't end up down stream and become a clogged muffler. Just don't tell the feds that you performed surgery on your converter. ;)
The above proceedure is for test purposes only. All emissions related equipment should be present on your vehicle to comply with federal regulations.