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Thread: New 540ci for my boat

  1. #1
    BrendellaJet
    Getting ready to order my new motor. 540ci, dart block, all forged rotating assembly,9.5:1 compression. Edelbrock performer RPM heads(rectangular port). I am anticipating 650 horsepower, and 700 lbs of torque. Considering the less than 1.3 horsepower per cubic inch, this motor should be stout and take a beating too. I haven't selected a cam yet, but im curious to see what everyone would recommend for a carb. Also what do you think about the cam. Its going into an 18 foot Brendella bubble deck, Jacuzzi Jet, I'll be boating mostly on the Colorado river.

  2. #2
    DUCKY
    Need to know a little more about your combination, specifically, what kind of induction and exhaust are your running, and what RPM range do you expect.
    [ January 13, 2003, 09:56 PM: Message edited by: DUCKY ]

  3. #3
    Infomaniac
    Where are you getting the engine?

  4. #4
    BrendellaJet
    Sorry, Forgot all about that. Basset OT headers, probably a victor manifold. This boat will be used for Cruising in the 3500-6000 RPM range, with an occasional 7500 rpm blast. I am not totally set on the Rectangular port heads, If you think an oval port would suit the needs better, then let me know. This motor will need to rev over 6K.
    Info- The kit is coming from Speedomotive.

  5. #5
    77charger
    IMO if you plan on reving to 7500 you will need a set of very hogged out ovals but i would take the square ports if it were my choice.Carb i think duals would be a good start or a dominator.

  6. #6
    DUCKY
    I think you will need to do more research on your hull, and pump before expecting to spin 7500 rpm. A Jacuzzi pump needs a lot of help to make it perform, depending on which pump you have. It would be smarter to turn a bigger impeller at 6000rpm. What does the bottom of the boat look like? Is it straight, with nice clean edges on the strakes Do you have a diverter or some other trim device? Not trying to crap on your parade, but a motor that turns 7500rpm can't be expected to live for very long, and all that power won't get you anywhere unless you get it to the water witht the proper pump and hull setup.
    [ January 13, 2003, 09:58 PM: Message edited by: DUCKY ]

  7. #7
    BrendellaJet
    DUCKY:
    I think you will need to do more research on your hull, and pump before expecting to spin 7500 rpm. A Jacuzzi pump needs a lot of help to make it perform, depending on which pump you have. It would be smarter to turn a bigger impeller at 6000rpm. What does the bottom of the boat look like? Is it straight, with nice clean edges on the strakes Do you have a diverter or some other trim device? Not trying to crap on your parade, but a motor that turns 7500rpm can't be expected to live for very long, and all that power won't get you anywhere unless you get it to the water witht the proper pump and hull setup. Ducky, I have spoken with Jack at MPD, he says this Hull is good to mid 80s. He will be blueprinting the pump before summer. I will be flipping the boat over for a new gel job, anything that needs to be addressed will be done then. I will be buying a diverter before the boat it put in the water.

  8. #8
    HighRoller
    I've seen a real nice off the shelf 900CFM Holley they sell that has the choke horn machined off already,I'm thinking that would work real good.You could go with an 825CFM mighty demon or a 1050 dominator but they might be too big or too small.As far as heads I'm no expert but from what I've seen the Edelbrock 345 aluminums are the best bang for the buck.I don't know if they come ported but they seem to be nice.If you can get them CNC ported from Edelbrock that would be worth about 30HP.The cam pick is gonna be up to you.Call Crane,Comp Cams or Clay Smith for a recommendation on a good grind for your chosen RPM range.Just my 2 pennies.

  9. #9
    Infomaniac
    BrendellaJet - If indeed your pump is set up to let your engine turn 7,500. It will not be an occational 7,500 RPM blast, it will be that RPM every time you nail it. Cruise RPM will be very high also.
    That size engine with those RPM's will need right at 1,170 CFM of carb. Bigger if your engine gives a good signal and smaller if a poor signal. Big ports, valves and intake or small etc.
    I would put a solid roller in it with a very good valve train including stud girdle. Let the cyl heads tell you what lift they like and the duration will need to have peak torque a little higher than cruise RPM. If not, it will not accelerate well if you nail it from cruise. This is not as critical on a jet because they typically run up to max RPM right away.
    Exact cam numbers will need to be decided after the remainder of the engine components are decided. It is difficult to predict what RPM your engine will make so cam choice will be a bit of a gamble.
    [ January 14, 2003, 06:49 AM: Message edited by: Infomaniac ]

  10. #10
    DogHouse
    540 is a big motor. I think it could use a little more head than a Performer RPM, which is only 315cc or 320cc for the Vic Jr ported version. I would probably use an AFR 335 CNC or maybe Dart 325 CNC head on a 540 that will see the kind of rpm you're talking about. As a reference, my 9.6:1 588 is using fully ported Dart 360 castings (not sure what the final port volume is but they have been substantially enlarged) and a matching ported Dart single plane manifold. It made peaks of 760ft-lbs @4700, 769hp @5700, and was still making 749hp at 6500. Cam is a Comp Cams roller, 256/262@.050, .714/.714, 108c/l. I initially thought the heads might be a little too big but the thing has a big fat torque band, cranks out great power and runs fine at low rpm too. Besides, now I can make it bigger someday without buying bigger heads!
    -brian

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