pump and impeller question

[W.O.T]

I am currently running a blueprinted aluminum A impeller (12jg pump) with a 600hp bbc. I want to run a B impeller to get to the higher rpms my motor was built to run. The bowl also has alot of vein work done to it. So my question is should i have my current impeller cut down to a B? Or just order a new B from berkely and keep the A onhand? I would also like to add a droop or straight snoot. Does anyone know what would work best on a 79 Challenger hull? I hear alot of different recomendations. I would love some good advice before i dump the money. heres a pic of the boat to get an idea of what im working with. http://a845.ac-images.myspacecdn.com/images01/6/l_13d8340a39f4eb5167a813b9b4d95c74.jpg
http://a718.ac-images.myspacecdn.com/images01/19/l_bb21806e2c304b22efefecc81af844dd.jpg

[SmokinLowriderSS]

That detailed A MAY be moving close to AA water volume. Personally, I'd cut the A, BUT, you can never go back. I'd have to be certain I was not going to mind the holeshot pulling loss of the cut, and want the RPM. If there's any chance of you going back, buy a "B", you could have it detailed later, BUT, you will probably need to re-do the wear ring clearances for it. That would leave you 2 setups (impeller, ring, shims).

[Mr. Crusader 83]

First question.
What kind of RPM's are you pulling now?
As for the droop or a straight snoot, every boat acts different. I went with the droop on my. I wish i would have got the one with the ride plate on it from Eddie Marine though. It made it ride high and loose on the water. The best thing to do is try just a droop, then work from there.
My .02

[Mr. Crusader 83]

Nice looking boat too.

[W.O.T]

right now it turns about 5300 rpms. i would like to be right around 6k to get a faster top speed. it has a great holeshot right now but im willing to give some of that up for some speeed. a loader grate is also in the plans. thanks for the replies. i have never made any changes to the current setup. last season was my first with a jetboat :)

[Mr. Crusader 83]

I say start with a droop and ride plate. then see how you like it. you will pick up speed but i doubt any rpm's.

[SmokinLowriderSS]

right now it turns about 5300 rpms. i would like to be right around 6k to get a faster top speed. it has a great holeshot right now but im willing to give some of that up for some speeed. a loader grate is also in the plans. thanks for the replies. i have never made any changes to the current setup. last season was my first with a jetboat :)
If you want 6-grand, you are looking at 2 cuts, from "A" to "C", and more loss in moderate RPM pulling power, and acceleration .... I stop liking it now ...

[67weimann]

If you want 6-grand, you are looking at 2 cuts, from "A" to "C", and more loss in moderate RPM pulling power, and acceleration .... I stop liking it now ...
or if you want 6 grand, more motor...

[QuickJet]

Get rid of the stock rock grate and get a good loader. My Bahner reacted very well to the Extreme loader.

[W.O.T]

Get rid of the stock rock grate and get a good loader. My Bahner reacted very well to the Extreme loader.
thanks, alot of people have recomended a loader and that it would really help me out. i am definitely going to invest in one

[W.O.T]

If you want 6-grand, you are looking at 2 cuts, from "A" to "C", and more loss in moderate RPM pulling power, and acceleration .... I stop liking it now ...
i know i will not get to 6k with one impeller size change. but its a start for now. when i bought the boat i was told it was an Ab impeller and i was really wondering why i couldnt spin higher rpms. i just pulled the pump apart and it is stamped MPD A. i feel better knowing its an A now that kind of explains my rpm level. i really want some higher top speed numbers and im hoping the B impeller, grate, and droop or snoot will get me into the low 80's. i gps'd the boat at 76mph before taking it apart.

[W.O.T]

I say start with a droop and ride plate. then see how you like it. you will pick up speed but i doubt any rpm's.
would running a droop without a rideplate not be a good idea? i have heard of the droop dragging and slowing the boat down without a rideplate. i plan on installing one just might not be any time soon (budget permitting)

[Hotfish]

Your impeller may have started out as an A but may have been cut already. Mine started off as an AA and then was cut but still is stamped AA. I would do a shoe and ride plate first then add a droop or snoot. That way you have alot more adjustability.
I went from 67 mph to 73 mph buy doing these changes on my Kachina and my motor is tired. I'm only pulling 4600 rpms with an A impeller.(I also set the pump back and staightened out the bottom)

[Duane HTP]

Does the boat have a shoed intake and ride plate?
Does it run real wet and need a lot of lift?
What position is that diverter in when it runs it's fastest?
Have you checked the bottom for hook?
These are just a few questions that should be answered before you spend any money.

[Scoobinator]

right now it turns about 5300 rpms. i would like to be right around 6k to get a faster top speed. it has a great holeshot right now but im willing to give some of that up for some speeed. a loader grate is also in the plans. thanks for the replies. i have never made any changes to the current setup. last season was my first with a jetboat :)
If your running 5300 rpms your probably not running 600hp every cut you do on the impeller will give a approximent 200 rpms more and the impeller that you have was probably built by Jack at MPD. If your looking for a hole shot you might check to see if you have a inducer already if not it would benefit you if you got one installed otherwise if you looking for more rpms you might want to change your engine set up.[

[W.O.T]

Does the boat have a shoed intake and ride plate?
Does it run real wet and need a lot of lift?
What position is that diverter in when it runs it's fastest?
Have you checked the bottom for hook?
These are just a few questions that should be answered before you spend any money.
the boat runs pretty dry when im on it. i have my fastest speeds with the diverter set to roost about 3-4ft above the water. yes it does have a little hook in the hull. i dont plan on doing any bottom work i just want to add a few bolt ons.