My 66 Olympique has a belly tank but I have a 74 Evinrude, 73 Harley and a 74 Sno-Jet that all have plastic tanks that fill though the front. Those plastic tanks all seem solid and not brittle but each one is a little different in shape and location of the filler tube. Somewhere I saw a video of a guy who modified his Oly to fit two plastic one gallon gas cans, it aint pertty but I suppose it works....