12' v hull and a Nissan 3.5b

Picked up a 12' v hull a while back with trailer for $250 doesn't leak a drop not sure of the mfr as it doesn't have a HIN. I picked up the Nissan for $225 and it runs great. So far I have rebuilt the transom with a 3/16 aluminum plate and some new treated wood not too concerned about the corrosion from the treated wood it's a crap shoot either way. I used it duck hunting quite a bit and with 2 people gear and a couple dozen decoys I got 6-7 mph which was nice because we were running timber alot. Today I got a chance to run it by myself with a gallon of gas and pfd I was still not able to get on plane it felt like it wanted to but didn't, I messed around with the trim a bit and no major changes. The engine doesn't seem like it is hitting max rpm but not sure. It has the 6.5" pitch prop on it. Is this about normal for this setup? Thanks

Also forgot to mention that I have painted the inside and put some bed liner down on the deck will be painting the hull when it warms up probably Parker's duck boat. Trailer is frustratingly short cant drop the tailgate because of the winch I think I would rather make a hitch extension as opposed to welding on the trailer it is kind of thin and rusty

I've got a 12' semi V with a 3.9 Merc on it. It doesn't mater if it's just me and a fuel tank or fully loaded with 2 people, batteries, trolling motor, fishing gear, and 6 gal of fuel. It's goes 6 mph regardless of how it's loaded. About the only thing I haven't tried is finding some little guy to drive it with only 1 gal of fuel on board to see if it goes any faster.