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Thread: How much HP do you think this engine makes?

  1. #1
    78Centurion
    I am new to all this and trying to figure out what this motor can do.
    To determine what pump Impeller is best for a new rebuilt JG Berkeley I am going to install. With a Place diverter. Into my 1978 Centurion 18Ft Bubble with light Hull.
    I think it has an A in the JC Berkeley now??
    It pulls approx 5200 RPM with the old JC doing about 69MPH with good hole shot (Cavitation is bad if you jump on it from a stand still)
    Engine made by Rex Hutchison in Sacramento
    454 Block Blueprinted
    Bored 70 over
    Compression is 9.8 To 1
    Isky Cam Z-55 RPM Range 3,500 – 7,500
    (Solid Cam lift .338, Valve lift .590, Dur 254 (.050), Lobe center 108 & Lash .028)
    Crank Stroke 4.00
    Valves: Intake 2.190 Exhaust 1.880
    Tunnel Ram with Two Vac Sec 1850Â’s 600 CFM each
    Mallory Electronic Distributor

  2. #2
    Blown 472
    Whos dyno?

  3. #3
    67weimann
    148bhp...

  4. #4
    inwo
    148bhp...
    Exactly No need to guess.
    .................................................. ............................
    Really it's 440 @ 5200rpm.

  5. #5
    suckin&pumpin
    I am new to all this and trying to figure out what this motor can do.
    To determine what pump Impeller is best for a new rebuilt JG Berkeley I am going to install. With a Place diverter. Into my 1978 Centurion 18Ft Bubble with light Hull.
    I think it has an A in the JC Berkeley now??
    It pulls approx 5200 RPM with the old JC doing about 69MPH with good hole shot (Cavitation is bad if you jump on it from a stand still)
    Engine made by Rex Hutchison in Sacramento
    454 Block Blueprinted
    Bored 70 over
    Compression is 9.8 To 1
    Isky Cam Z-55 RPM Range 3,500 – 7,500
    (Solid Cam lift .338, Valve lift .590, Dur 254 (.050), Lobe center 108 & Lash .028)
    Crank Stroke 4.00
    Valves: Intake 2.190 Exhaust 1.880
    Tunnel Ram with Two Vac Sec 1850Â’s 600 CFM each
    Mallory Electronic Distributor
    i have a 77 18' centurion bubble and I added a cavitation plate and I have to tell you WOW what a diff the nose barely rises

  6. #6
    396_WAYS_TO_SPIT
    I am new to all this and trying to figure out what this motor can do.
    To determine what pump Impeller is best for a new rebuilt JG Berkeley I am going to install. With a Place diverter. Into my 1978 Centurion 18Ft Bubble with light Hull.
    I think it has an A in the JC Berkeley now??
    It pulls approx 5200 RPM with the old JC doing about 69MPH with good hole shot (Cavitation is bad if you jump on it from a stand still)
    Engine made by Rex Hutchison in Sacramento
    454 Block Blueprinted
    Bored 70 over
    Compression is 9.8 To 1
    Isky Cam Z-55 RPM Range 3,500 – 7,500
    (Solid Cam lift .338, Valve lift .590, Dur 254 (.050), Lobe center 108 & Lash .028)
    Crank Stroke 4.00
    Valves: Intake 2.190 Exhaust 1.880
    Tunnel Ram with Two Vac Sec 1850Â’s 600 CFM each
    Mallory Electronic Distributor
    Are you running water to your headers? If so that cam will NOT work!!!!!!! Way too much overlap! If you run dry, then your fine. Make sure that you tie both vac secondary cans together. YOu want to secondaries to open equally!
    Ill take a long shot and say an honest 500hp.

  7. #7
    78Centurion
    i have a 77 18' centurion bubble and I added a cavitation plate and I have to tell you WOW what a diff the nose barely rises
    There doesn't seem to be a lot of Centurion Bubbles. Where did you get the plate? Have any pic's?

  8. #8
    78Centurion
    Are you running water to your headers? If so that cam will NOT work!!!!!!! Way too much overlap! If you run dry, then your fine. Make sure that you tie both vac secondary cans together. YOu want to secondaries to open equally!
    Ill take a long shot and say an honest 500hp.
    The boat was set up with water and it seems to be ok. What can happen?
    I want to run through transom Lightnings water jacketed soon.
    I was thinking the HP was around 450 to 500. So the A impeller.
    I plan on doing the Vac Sec link.
    Thanks for the input.

  9. #9
    QuickJet
    The boat was set up with water and it seems to be ok. What can happen?
    I want to run through transom Lightnings water jacketed soon.
    I was thinking the HP was around 450 to 500. So the A impeller.
    I plan on doing the Vac Sec link.
    Thanks for the input.
    When both the intake valve and the exhaust valve are open at the same time reversion can take place and suck whatever is in the exhaust (usually spent gas) back into the cylinder. When water is added to the exhaust it can get sucked back in as well.
    Water doesn't compress and it will lock an engine up real quick destroying stuff on the way.
    I've had cams bigger than yours and got away with it.

  10. #10
    suckin&pumpin
    There doesn't seem to be a lot of Centurion Bubbles. Where did you get the plate? Have any pic's?
    I got the plate from a friend who had it in his garage, I have had a hard time finding out anything about old centurion except that they started in 1978 but my title says 1976 but first sold in 1977. I have pics but cant figure out how to post em LOL not good with computers more of a outdoor type.

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