I would use a 1/2 inch pick up in the tank and to the pump, 1/2 inch return, two #6s to the carb. is good. The #6 return will probally be okay, depending on the pump you use. I use a Magnafuel 300 pump on my Duster with a stock tank and a #10 from the bottom of the tank to the filter and to the pump, #8 return line welded into the tank in the stock location from the pump, #8 to the four port regulator mounted on the elephant ears(two piece motor plate) and three # 6 to the tri power carbs. I had a Magnefuel 275 pump on the car at first when the motor made 612 hp and I had to switch it to the 300 when I upgraded the heads, compression and increased the C.I. a little, this was detected by the Innovate LM1 showing the motor going lean at WOT I had treid to fatten up the jets and the AFR remained the same