[Roadsters] battery cable help

[toolmansj2 at comcast.net]

Does anyone know the length of wire I need to build a positive battery cable. I will also build a negative cable with the same wire. I did not get a positive cable with my car and plan on buying some at lunch time today. I plan on using #4 welding cable and it is quite expensive like $4.25 a foot. This is what they sell at the auto store close to my work. Any advice?

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1969 2000 U20 
2007 Titan 4x4