I'll try and give quicksilver a call. I'm aware my motor is the 51ci engine, it's the 60hp model. According to outboard jets even back then the 50hp jets although the same AG model had the 6 5/8" impeller and liner where as the 60hp AG model was suppose to come with a 6 7/8" impeller and liner. I'm not sure what my rpms are exactly no tach, I know I should get and plan on it. My motor is a 60hp I've just been running the smaller impeller because that's what the jet I bought came with. I bought my outboard jet lower used because it was only $800 vs around $2000 for a new one. Had I bought new which I didn't do because I couldn't justify the cost of, I would have got one with a 6 7/8" impeller and liner. Just going off of the sound of the engine at WOT it sounds like it's revving a little high, I know get a tach to be able to actually know. I plan on getting a tach so I can compare rpm before swapping around impeller's and liners. I will compare speed as well, but it will be a little subjective as when I make the switch I'm also switching to one of the rock proof UHMW intakes, which I've heard usually hurt top speed 1-2 mph. My hope is that the speed I lose for the UHMW intake I will gain back with the 1/4" larger stainless impeller and wind up with the same speeds but have the tougher intake. I usually don't keep it 100% WOT while running unless I really want some speed to go across a shoal or riffle in a river just because it does seem like the rpm's are a little high.
As for the UHMW intake I will report my thoughts on that as well. Main reason I'm going with it is I tend to have a lot of logs to go over and some spots with riffles that are impossible to go through with out catching some larger rock sticking up a little higher than the rest. The logs are always good at catching the intake as you go over. I'm surprised I haven't done more damage to my intake already. I'd say the one thing that has saved it so far is my motor is older doesn't have power trim and can kick up easily with the tilt assist when the motor isn't locked down. Which I never run it locked down so it can kick up. Thankfully this pic has been the worst outing and didn't do any major harm to the intake, but bent the intake bars up pretty good.