Battery wire gauge mis match . ok?

gdizzle said
I am replacing battery cables, was able to replace the Ground side without issue. However the hot side currently has 4g heading directly to starter, but also has a 8g heading to the starter relay (mounted on the firewall).
The issue is buying a replacement cable, has the 4g, then has a pig-tail which is only 10g.

Is it safe/acceptable to run a 10g wire to the starter relay, instead of the current 8g?
Or is it safe to use my current 8g (old)wire, cut it and splice it to the 10g pig-tail from the battery terminal?

run the replacement wire. You have to remember that the standards today for wiring is better than the 70's and also the quality of the copper alone is better as well. Also, that 8g wire only sends power down to the starter solenoid that throws out the starter pinion gear. It's not a lot of amperage to make that plunger move.