Hi, I have recently purchased a '73 32 foot burnscraft with a volvo penta stern drive and a 350 chevy engine. I get about 1 mile to the gallon. What size prop should I Have? For me to run about 10 mph I am turning about 3000 rpm. I think my prop is 14 1/4 inches in dia. Everyone that I talk to tells me that I need a much bigger prop,is this true? I would like to be able to cruise at about 15 to 20 mph at about 2000 to 2500 rpm, is this possible? Can anyone help? Thanks!