If the battery turns out to be okay and you need to replace the cables, I suggest buying lengths of 0 or 1 guage wire from NAPA and their 'fusion' battery cable ends- They come preloaded with solder and flux. You just strip the end of the wire 7/8" and push it into the terminal while you heat it, when the solder melts and it hits bottom yer done, and there's no risk of a bad connection between the terminal and the cable, which I've run into with 'clamp ons'.

'51 Chevy 1/2 ton w/'62 261, HEI, offy, fentons, dual carter/webbers, t-5 & 12 bolt posi