SBC Engine Build
+ Reply to Thread
Results 1 to 7 of 7

Thread:
SBC Engine Build

  1. #1
    Captain Rehab swampfox44's Avatar
    Join Date
    Jun 2009
    Location
    Lexington , SC
    Posts
    39

    Question SBC Engine Build

    I've got a '68 Cheetah 16' I just bought to fix up.It has a 4 bolt 350 in it now.It has a Berkeley 12JA pump with an aluminum "A" impeller and Place Diverter.My options are pretty open right now on engine build.
    The engine had a set of 882 casting,open chamber heads. I've got a pair of Double Hump heads and also a pair of new aluminum big valve,closed chamber heads.I was thinking along lines of the aluminum heads,a Comp Cams XM270H cam kit , Edelbrock Performer EPS intake,750 Holley and has a pair of long tube headers which look to be an old set of GIL or REWARDER's.As far as compression, 11.0,10.01,9.5?. I'd like to be able to run pump gas and be able to cruise as well as open it up.
    My second thought was same setup as above,but with the Comp Cam XM278H and a Edelbrock Performer RPM Air Gap intake.I've also got a 1968 Chevy Z28 302 H.O. Factory High Rise Aluminum intake,GM #3917610. Didn't know if that was a good choice or if it was geared more to high RPM.
    I'd like to have a fun,fast jet boat,noy just a wideopen only boat.Decent fuel efficiency never hurts either!!! Any and all input would be greatly appreciated.

    Thanks
    Last edited by swampfox44; 06-20-2009 at 05:25 PM.
    SwampFox
    '68 CHEETAH
    383 STROKER

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member GT Jets's Avatar
    Join Date
    Jun 2008
    Location
    Morgan Hill
    Posts
    2,234

    Default

    First off welcome to PB.

    Secondly, you will be in for an impeller change with either set up. a small block set up to run 5000-5500 RPM will never get there with an "A" impeller.

    The heads camshaft and rockers are the most imprtant decisions that will either make or break the success of your build.

    I would recommend a 10.0 or 10.5:1 CR on either setup, the pump gas wont limit you too bad either way.

    I have built a few small blocks for jets and if it were me I would stick to the closed chamber heads, plan on running this thing pretty hard as far as RPM, these are not torque makers by any means.

    I'm sure you will have 100 other opinions on how to build it, the small block is a very inexpensive way to go and they run pretty good.

    Make sure to pick up a large capacity jetboat oil pan and an oil cooler is recommended also. (I have personally burned the paint off the oilpan on two different occasions).

    Good luck....and pictures are a requirement

    GT
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  4. #3
    Senior Member Delemorte's Avatar
    Join Date
    Mar 2008
    Location
    Charlotte, NC.
    Posts
    1,553

    Default

    Love my SBC.. i would seriousy consider a smaller impeller. My 350 spins a B 5000 RPMs... It will however spin it all day along.. Assuming gas holds out..
    Quote Originally Posted by jetboatperformance View Post
    the ensueing fire would likely be extinguished by the sinking however

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member gregb's Avatar
    Join Date
    Jan 2008
    Location
    Redondo
    Posts
    375

    Default

    I don't know what your budget is, but I think for not a whole lot more you could build a 383 stroker motor, and cubes definitely help with a jet application. I had a stock 350, with 8.5 or so compression, a 280H comp cam, Edelbrock RPM intake, headers and a 750DP and it turned a B impeller 4700-4800 for the better part of 17 years. Was ol' reliable. Small blocks can be a lot of fun in a jet boat. Still have the short block for a spare. Your first cam choice with about 10 to 1 compression, the Air Gap, and the aluminum heads would be my choice from your pick.

  7. #5
    Senior Member jetboatperformance's Avatar
    Join Date
    Dec 2007
    Location
    Atascadero Calif
    Posts
    7,463

    Default

    Welcome to The boards , we do quite a few Small Block jet projects a season , suggest you look hard (research) that dynamic compression those combinations you described will make , you maybe surprised , particularly if you wish to run 91 octane Josh has spent a considerable amount of time on this and has a lots of infornmation to share if you need help Tom


    ps Gregs advice re The "stroker" is sound , Joshs boat (Small block stroker) runs just shy of 80 ,pulls hard and turns an A impeller 5K


  8. #6
    Captain Rehab swampfox44's Avatar
    Join Date
    Jun 2009
    Location
    Lexington , SC
    Posts
    39

    Default

    Yes,some advice would bve appreciated.What setups are any of you running as far as 350's and 383's? Cam profiles,intakes and compression.

    Thanks
    SwampFox
    '68 CHEETAH
    383 STROKER

  9. #7
    Senior Member gregb's Avatar
    Join Date
    Jan 2008
    Location
    Redondo
    Posts
    375

    Default

    My current engine is a 383, 9.8 compression, Sportsman heads, RPM Air Gap intake, 750DP, Comp XR282 hydraulic roller cam, roller rockers, Bassett headers, a Mallory HEI (and I finally locked out the timing), turned an A impeller 5000, 70mph in an 18 foot boat with 3 people in it, just had the impeller cut to a B and detailed, haven't had it back out. A 16 footer, well that would be that much more of a blast, you'd surprise the s*** out of a few of big blocks........before putting more power to it make sure your pump is in order. Small blocks are easy and cheap to find, if it runs now I'd pick up another block to build and enjoy some time on the water, summer is here you know.

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95