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Thread: BBC Head Choices

  1. #1
    V1800J
    Which heads are better for all around jet boating, square or oval port for 454? I believe square ports flow more air and work better once the rpm's get going but I think oval port will build rpm's faster. If I'm wrong let me know. I want something for pulling skiers, cruising and maybe hit 75 mph on occasion. I can taylor the other engine parts accordingly. What I'm trying to avoid is a sluggish motor at lower rpm's. Any and all advice appreciated.

  2. #2
    Heatseeker
    As you already know, rectangle ports don't really give you much until you get in the higher rpms. With a 75 mph jet, you're most likely to be running in the mid 5000 rpm range, unless you're running something smaller than an A impeller.
    So, for all around jetting, the big ovals work out pretty good.

  3. #3
    lilrick
    As you already know, rectangle ports don't really give you much until you get in the higher rpms. With a 75 mph jet, you're most likely to be running in the mid 5000 rpm range, unless you're running something smaller than an A impeller.
    So, for all around jetting, the big ovals work out pretty good.
    yah...what he said.

  4. #4
    396_WAYS_TO_SPIT
    Big ovals have an impressive bottom end. 2 of my friends are running big ovals and thier holeshot's are very impressive..

  5. #5
    Hipshot
    Hello V1800J, It would be easier to answer your question factually if you provided more details about your set up. What boat do you have? What internal engine modifications have you done or are going to do. What size impeller are you spinning? In my opinion you shouldn't "taylor" the other engine parts to your cylinder heads, you should instead figure out exactly what you want to do, how much money you have to spend, what parts do you have for a base build up, then design the engine as a package deal to do what you want it to do.

  6. #6
    V1800J
    I know the 781's are the big ovals. Are there any more castings that are the big ovals. Thanks.

  7. #7
    Hipshot
    049 are big ovals and usually easy to find.

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