JennyB, with that Hull and HP, you are talking about a major performance improvement and TINY diffs in fuel burn.
What the heck is the diff? 6 Gals/per full day versus 7 gals? By this summer that adds up to what?$2.50. A Rapala costs $10.00.
Power up. If you are sweating the gas mileage/cost effectiveness in a older 70 2 stroke v 90 Etec, you need a new hobby!