I have the 856 on my 03 210 and really like it. Runs about 3800rpm at 30mph, about 400rpm more than the 644. Jumps on plane even with 2500lbs. (sea level) I have not noticed a fuel use increase at wakeboarding speeds probably due to less fuel used on each start. (we fall ALOT!) I am sure on a long run with few falls or high speeds, fuel use would be significantly higher over the 644. Perfect pass holds speeds a lot better with this prop. Smoothness, wake and rooster seem the same as the 644. What prop do you have now?
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