There really isn't any reason your pump won't push the boat to 70mph. 

But, you might find that even without a rev limiter you might not have enough horsepower to spin it to 6000rpm.  A jet pump works a lot like a dyno, it'll suck up every bit of HP you can throw at it, then if you're lucky enough to overpower the pump, you upgrade the pump and start all over again trying to make enough HP to overpower the pump again 

How fast was you going at 5000 rpm. with the yj energizer kit. how big is the boat.

With an Energized YJ, loader, and Place Diverter on my 19' Charger, we've been able to hit a best of 64 MPH.........downriver..........with a tailwind........running solo. 

Now granted, it's a big, heavy sucker running a warmed up Olds 455, so I don't think 70 is out of the realm of possibility/probability on your float.

Sergio is the "caretaker" of my boat, buying it at some point, or so I'm told, but both of us try pretty steadily to blow up the Olds so we have an excuse to throw a 460 in there. Fugger won't co-operate and just break! I'm pretty sure if I toss another 200 or so HP at it and swap out the B impeller that's in it (Most Energizers were equipped with a B, just an FYI) with an A or an AA I can get the Turd to hit 70.

I've got a built 460 here to do it, but I've also got a newfound respect for the Olds 455. The life it's had before I owned it not even into consideration, Sergio and I have BEAT the LIVING SNOT out of this thing, and the jury's out as to whether it's co-operating or NOT co-operating, depending on how you look at it.

Ray   

O ya I wanted to ask what rpm were u pushin dwn wind at 64?

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Thanx daniel I was thinkin yhat after what crew said u worded it lil better for me im thinkin im right at 450-475hp so as crew said I need more money for power thanx again daniel u made that very easy to understand man that a big jump in power for 1000 rpm? 

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