I'm installing a new "custom" tank in my 79' brat, only thing is im installing it in a different location from the stock one and the stainless/aluminum fuel lines are not exactly flexible. How should I go about changing to rubber lines? and should the return line and supply line be the same length?

no rear reason for the supply and return lines to be the same length, the pump doesn't really know anyways. and with rubber lines, really try to minimize it...only for joints, places that need to flex, etc. you don't want rubber lines running under your car to get hit by a rock or something, and I personally wouldn't want fuel flowing through the passenger compartment in rubber lines.

~ErikE