you have the older 1600i with distributor ignition yes?? Then its easy.

The rev limiter on these cars is on the rotor arm in the dizzy. Its a spring on a weight that as it spins to a certain speed allows the contacts to stop connecting and then stop firing (lots of flames if you do this right!!! )

Anyway, just go out and get yourself a rotor arm without the limiter on it. Finished!!