Impeller/bowl help

[496jetboat]

im not to sure what Impeller i need. im looking to replace my Impeller. i would like more top end mph's. i have a A Impeller right now. the boat has a 496bbc the roller cam makes power to 6200rpm. my question is dose a AA or B Impeller give you more mph. also i have a 12jc pump will the 12jg bowl fit my pump? thanks for any help.

[junkyardhunter]

Yes a you can put a JG bowl on a JC pump.
SPAM I have a bowl & impeller for sale
http://www.***boat.com/forums/showthread.php?t=147472

[76miller]

496, If you want more rpm/mph go with a "b" impeller, it is a smaller impeller than what you have now. You might lose a little hole shot, but if your worried about that you could add an inducer and get back your "a" hole shot, with your "b" rpm/mph gains. The jg bowl would be a good upgrade also. You then have the option of a droop snoot.

[Skip3]

I could be wrong here but I think they need to know what RPM you are turning with the A.If you are not getting to use all of the 6200 then you would try an B.If you turn that A to 6200 than you would want to try the AA. By the way if that's a stainless A i 'm looking for one

[junkyardhunter]

im not to sure what Impeller i need. im looking to replace my Impeller. i would like more top end mph's. i have a A Impeller right now. the boat has a 496bbc the roller cam makes power to 6200rpm. my question is dose a AA or B Impeller give you more mph. also i have a 12jc pump will the 12jg bowl fit my pump? thanks for any help.
What RPM are you spinning your old A cut impeller.

[496jetboat]

its spining 6000 rpm with the A, will the 12jg bolt right up to the 12jc ?

[Devilman]

its spining 6000 rpm with the A, will the 12jg bolt right up to the 12jc ?
Yes, it'll bolt right up. I swapped my C bowl to a G a few weeks ago, so I could utilize a droop...... Money & time well spent, I might add.

[flat broke]

How much more horsepower does the motor make between 6k and 6200? Unless it's a lot, I wouldn't cut down to a "B". That kind of RPM with an "A" impeller should land you in the high 700hp range at that RPM based on what I was seeing with my last pump/engine setup.
What are you running for a loader/shoe/etc? Do you know what your inlet pressure is at WOT? The reason I ask is because if you aren't loading the pump hard enough, you are giving away speed.
Additionally, one of the more important questions should be, what type of boat, and what do you want to do with the boat.
But if the boat is loading well, and the hull isn't too big, the generic reccomendation would be; buy an A cut and run it. If you want a little more RPM, the impeller can be trimmed down a touch ( not as small as a "B") to put you right on top that 6200RPM.
Chris

[Nucking futs]

I have a bowl with a stuffer,5* wedge and nozzle housing for sale in the spam section.....

[496jetboat]

its a 1972 tahiti tiger 18ft. im not looking for more rpm i want to go faster top speed. pressuers i dont know, but at 6000rpm the boat is runing 79mphs on gps so i would quess its loading fine. more or less im new to jet boats, i bought the boat it had a 396bbc in it that let go so i built the 496 to go fast, the shop that did all the machine work in walnutcreek ca told me it should make a bout 650hp if not more.
i was thinking of puting a AA impler and a 12jG bowl and droop on the boat
to get into the 80's, will this set up help?
will my place diverter fit your dowl/stuffer?
thanks alot for all the help and sorry if i left any thing out im new to boats.