Get a couple of new battery cables made up from #1 or larger welding cable (not coarse strand battery cable). Make the ground cable long enough to attach as close as possible to the starter housing- - - -ideally, under one of the bolts that attaches the starter to the engine.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!