Battery ground cable gauge??

[firebob]

My battery is relocated to the trunk and my ground wire has always been attached to the side of the frame at the rear of the car. Some say there can be problems using the frame and body as the path for ground to the motor. It's been that way along time but now without problems but I'm thinking about running a ground cable all the way up to the block. No peticular reason except I don't ever want to have to wonder if this is causing elect problems in the future.

I was wondering if #4 AWG wire is large enough to use for ground? The only accessories I have are the MSD box, air conditioning and a regular radio. The cable will be about 10-15ft long.

Robert