One of my good friends and myself just finished the new motor for my boat, started with a 460 long block had the block completely gone threw, cylinders honed, rotating assembly checked and balanced, we went with Keith black .020 over flat top single relief Pistons, D3ve-A2A heads decked with new valves, springs and seats cut. Went with comp cams roller cam .521 lift, 270 duration, edelbrock performer intake, with a Holley 850 double pumper with mechanical secondary's and full MSD ignition. She's at 10:1 on pump

I'm running a stock Berkeley pump with an A empeller.

The motors spinning to 5800-5900 RPM

Last weekend was the first time running it, in shitty choppy conditions she ran 63 on GPS.

Now that you know the gist of it, what can I do to the pump to get some more MPH out of her. From a dig she is cavitating like no body's business, if your cruising at 3k and pedal it she goes good without any cavitation. But I feel the pump is holding her back. I don't have a droop or diverter. But I have a Jet-O if that makes any difference. The hulls a 19FT substance hull similar to the Elimantor bubble deck. She's got some weight to her.

I know you can have all the power in the world but if your pump cannot push the water threw it's a waste so where should I start?




Sent from my iPhone using SoCal Jet Boats

Looking over some of your posted engine specs, it’s highly unlikely you’re putting out high 600 to 700 HP with that combo; I’d give it maybe 475-525 HP. Good assumption that your pump is tired and could use some beneficial upgrades. Unsure of what type of bowl you have, but to eliminate much of your cavitation issue an inducer would be needed. A loader grate is a big help also to help load the pump, droop snoots are good to get more of the hull out of the water for less drag. A Place Diverter is a very good investment on any jet boat for all round performance. If you’re really feeling the burn in your pocket with money you also can have the intake removed, machined for a shoe/ride plate and even possibly set back. All these changes will equate to higher performance, pump efficiency and higher MPH. To choose the correct impeller the engine really should be dynoed to see the true numbers and torque curve. Just like a drag car with an automatic trans, the converter MUST match the camshaft profile and useable rpm range. But, just like everything, one has to ask themselves how serious are you? What are your goals with the equipment and how much are you willing to spend, all this can become rather costly. Good luck with your project put the money where it counts the most.

its possible youre making more power now and just "blowing" it out

But yes, you should be nowhere near 5800 rpm with that thing. Even if it had a B impeller...

im all of 625-650 on the bottle and i barely spin a B- to 6200

welcome to my hell.....

I have a pretty fresh pump but its not "built" by any means. Just tightened up the clearances a bit, new impeller, etc. I have no diverter or inducer...

if i flat foot it from idle. It will literally bounce the rev limiter all damn day long. If im cruising and stab it it hooks hard and pulls good.

My money is on your pump is worn out, and needs to at least be inspected for excessive clearances. You have a diverter so thats good. Keep it pointed down on the launch, see if that helps.

But an inducer would help too.

Pull the bowl, get some playdoh and measure your clearances

That is the craziest diverted set I've ever seen how well does it work