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
    Likes: 0, Points: 0, Legacy Rep: 10
    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?

    Thanks
     
    Last edited: Mar 27, 2008
  2. jim lee
    Joined: Feb 2007
    Posts: 368
    Likes: 20, Points: 18, Legacy Rep: 247
    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 : http://home.pacbell.net/jmcclure/

    And here's a video all about Jack (Owner or MPD) : http://www.youtube.com/watch?v=_ugp8xfglNw

    Good luck!

    -jim lee
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.