Is my fuel tank too small? :-)

I am putting in a 55 gal tank, I currently am running 2 Merc 5.7l 300hp tempest motors. The boat has yet to get wet with me at the wheel so I have no idea what kind of mileage I will get. What are your thoughts?

My Nova holds 104 gallons for twin 270 mags.

That's a little small. My 311 has twin 500's and gets a little better than 1 mpg . If you can eek out 1.5 mpg with the small blocks you need gas every 60-65 miles or so. (leaving some reserve)

that is way too small...the 292 fastechs with twin 6.2's have 113 gallon tanks...my dads non go fast boat with (1) 350 mag has a 55 gallon tank. you will not have good range with 55 gallons on anything twin screw. trust me.

I agree with the above....you might eek out 2.0 mpg and 55 gal will go quick.

I have a 242 with twin 383's. My tank is 107 gallons. I get about 1- 1.5 miles per gallon. It also depends a lot on how you drive it.

If you ever do a long run thats only about an hour.If you are sure you will always stay local you are fine.But 55 gallons is not a lot for twins even small blocks.