Not to be argumentative, but it is absolutely possible. The hard line is 5/16 running from the tank to near the pump, then it goes to a soft line to the pump. The pump can be adapted from 3/8 to 5/16 there and the line from the pump to the carb can either be adapted to the 3/8 pump or replaced with 3/8 line. Then later, you can change out the fuel pick up to a 3/8 and lastly change the hard line out to a 3/8. Probably not the most effective method but on a budget it would work fine.