I reckon your easiest bet, is to source another cable, of similar grade and fit new ring fittings to it. Keeping the one on the tappet cover where it is, just clean the area and then scrub the area of contact with a wire brush. The other larger ring fitting fit on top of the mounting bolt for the carb, using another nut to secure it. Just ensure all contacts are cleaned and then scrubber with a wire brush to ensure a good "connection".

It would be a good idea to go over all your grounding points and do this.

Here is an example of a good grounding kit that you can buy. I took the time to make mine, using decent 8 and 4 guage power cabling for sound systems.

Hope this helps.
