Rebuilding a 350 small block with Berkely jet

Discussion in 'Jet Drives' started by ejkob, Mar 27, 2008.

  1. ejkob
    Joined: Mar 2008
    Posts: 4
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    Location: Missouri

    ejkob New Member

    I have a 72 Glastron 18.5ft fiberglass classic with a small block 350 and a JCB Berkeley jet drive. I have been in the process of restoring the boat and this year I want to rebuild the motor. I plan on replacing the old Rochester qudrajet carb with a new Holley. Last year at the upper end of the throttle, the motor acted like it was missing or starving for fuel. For now, I am looking at a 600 CFM but I am being told that the Holley replacement for a Qjet is 650 to 750CFM. Can someone quide me as to the correct carb to get and as I rebuild the motor, what CAM should I consider to power the jet. After all the work is complete, should I change back to the stock A impeller?

    Last edited: Mar 27, 2008
  2. jim lee
    Joined: Feb 2007
    Posts: 368
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    Location: Anacortes, WA

    jim lee Senior Member

    A 650 spread bore would work great. I've heard the center hung float bowls are the ticket 'cause they take the rough ride better.

    A impeller B, C or D it all depends on the power band of your engine. Building a jetboat engine is NOT like building a car engine. Choose an RPM that you feel comfortable with. Dump ALL the HP at that RPM. (Like a 2 stroke, very peaky) Ignore those that talk about torque. Once you choose your Max HP RPM, build the engine. Once the engine is built and running, start with the A impeller and have it trimmed 'till you hit your target max HP RPM. Done!

    Here's THE MAN for jetboat questions :

    And here's a video all about Jack (Owner or MPD) :

    Good luck!

    -jim lee
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