I made another post and was directed here...My friend is restoring a '68 Charger 383, 4 barrel, auto..the person helping restore it accidentally,prematurely threw out the sending unit.. Would his be a single, 5/16" line? Or would there be a need for return line? I'm guessing it was a single line but want to find out for sure for him..if it's a dual line, what are the sizes?