I have been looking at the Lowrance EP-10 fuel flow sensor that hooks up to their plotters (Just bought the Lowrance 6500C).

Some info about the sensor:
3/8" tubing
0.5psi back pressure at 20 gallons/hour
1.0psi back pressure at 40 gallons/hour
Measure range: 0.6-45 gallons/hour (It works outside the range as well)

The engine will at WOT need about 75 gallons/hour.

Will this sensor work with my setup?!

I think with the 3/8 tubing it will cause a restriction.....

Yes, that's my tought as well...