Fuel tank replacement options opinions needed

[Fitz]

When I bought my 1975 V20 it had only saddle tanks (40 gallons total). I wanted additional range for offshore fishing runs, so I added an 18 gallon Tempo Model TP18SC under the bench seat that I added in the rear. I routed each of the tanks into a three-way manual switch that I mounted on the starboard side of the seat. That setup has always worked great for me.