Horsepower!!!!!
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Horsepower!!!!!

  1. #1
    jetboataholic HawaiianJet's Avatar
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    Default Horsepower!!!!!

    I don't know if you guys will be able to answer this for me because of all the factors that go into determining horsepower, but I'm just looking for a real rough estimate. So here it goes, what would be the approximate horsepower I could expect out of my engine?

    The engine is a Chevy 427T bored out 0.060" with flat top pistons. GM iron big oval "Hi-Per" heads. I am going to assume stock cam and crank and rods. I have a Mallory Hyfire ignition box, this big black box for a coil, and a marine Mallory single points distributor. I have a 850 CFM Mighty Marine Demon carburetor on top of an Edelbrock Performer Z-0 aluminum manifold. The jet sizes on the carb are 88 and 93. I have a Bassett long collector OT water injected headers.

    If you need to know anything else let me know and I will find it out for you. And if you need to see a picture of something else, I can provide that too. I have hundreds of pictures.

    Here are some pictures of the engine.











    Thank you.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.
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  3. #2
    jetboataholic HawaiianJet's Avatar
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    Here are some more pictures.







    Thank you.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.
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  4. #3
    mo balls than $cents$ IMPATIENT 1's Avatar
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    400ish lose those heads, stroke that dude to a 540 nice looking set-up btw

    .60over 427 is a 439
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    jetboataholic HawaiianJet's Avatar
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    Heads will go when I find $1000 laying on the ground, so I can buy some nice rectangular port Merlins, and a Team-G or Brodix intake. This is just a start for now. First boat, don't want to get too crazy. I've got a very heavy foot! It'll get a nice cam and a roller setup too.

    You really think it will put out 400 HP? That would be sweet, I was think more along the lines of 300 HP or so.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.
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    mo balls than $cents$ IMPATIENT 1's Avatar
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    Quote Originally Posted by HawaiianJet View Post
    Heads will go when I find $1000 laying on the ground, so I can buy some nice rectangular port Merlins, and a Team-G or Brodix intake. This is just a start for now. First boat, don't want to get too crazy. I've got a very heavy foot! It'll get a nice cam and a roller setup too.

    You really think it will put out 400 HP? That would be sweet, I was think more along the lines of 300 HP or so.
    need alot more info for a better guessestimate compression, cam info, etc. are those the big ovals?

    just helped put together almost the same motor (roller 439) last fall with flat top arias blower pistons, eagle hbeams, forged gm crank, 680 lift solid roller nitrous cam , big oval closed chambered heads, and it is in the 440-450hp range by the impellor chart on his fresh pump. pushes his tx19 to 78 on motor, he hasn't put the nitrous to it yet but was talking about doin it this weekend. it was built to handle a ton of nitrous beatings.
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  8. #6
    jetboataholic HawaiianJet's Avatar
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    Quote Originally Posted by IMPATIENT 1 View Post
    need alot more info for a better guessestimate compression, cam info, etc. are those the big ovals?

    just helped put together almost the same motor (roller 439) last fall with flat top arias blower pistons, eagle hbeams, forged gm crank, 680 lift solid roller nitrous cam , big oval closed chambered heads, and it is in the 440-450hp range by the impellor chart on his fresh pump. pushes his tx19 to 78 on motor, he hasn't put the nitrous to it yet but was talking about doin it this weekend. it was built to handle a ton of nitrous beatings.
    Yes, they are the big ovals and they say "Hi-Per" inside of them. I ran the numbers on them once, but I can't find them anymore and I keep forgetting to write them down when I go out to work on the boat. I don't know any of that information, I bought the engine completely assembled for cheap, my best guess would be that it has the stock 427 cam in it. The RPMs will probably be low because of the stock? cam, But the cam is the first item on my hit list of things to replace when I get the money. If I had to guess at the compression, I would say 8:1-9:1, but I really have no clue, it has stock stroke and 0.060" over pistons, but I just don't know the compression height, so I can't figure out the compression, can only guess at it.

    I have a freshly built pump with an aluminum AB impeller, so it should be able to spin it pretty good, and a reworked bowl, the vanes were cleanup and smoothed out, when it was sent out to an unknown jet shop, probably 10 years ago or more, and the boat sat for about 10 years before I got a hold of it.

    My best guess with a stock cam and everything is somewhere between 300 HP and 400 HP, and I think 400 is pushing it because that one you mention has a lot better parts in it than mine, it's a roller set up too, I just have Hyd. flat tappets. But again I really have no idea how to figure it out, and don't know what a stock 79' 427 engine puts out.

    Thank you.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.
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  9. #7
    mo balls than $cents$ IMPATIENT 1's Avatar
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    i bet it runs good your impellor is about right to keep the motor pulled down to around 5krpms. you've gotta really good start with this motor, you can always stroke it big in the future etc.. good luck and i hope break in goes well
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  10. #8
    jetboataholic HawaiianJet's Avatar
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    Quote Originally Posted by IMPATIENT 1 View Post
    i bet it runs good your impellor is about right to keep the motor pulled down to around 5krpms. you've gotta really good start with this motor, you can always stroke it big in the future etc.. good luck and i hope break in goes well
    Thanks.

    Don't know, never seen it run, it didn't even have a motor when I bought it. I've heard some stories about the old girl though. The previous owner claims that it was running like 93mph when he had it. But I highly doubt that, it only had a 454 in it, he might of been running 73mph but not 93mph, it had less on the pump than what I have on it now. It doesn't even have a ride plate, so 93 is out of it's league for now. Until I land that nice big architecture job after I get out of school, and can start pumping money into stuff. Can we say EFI and turbos.

    I sure hope so. If you think it will turn 5k then I might have to bump the rev limiter up a little. I either have the 4000 or the 4300 pill in it right now.

    This will be be break in attempt #2. #1 didn't go so hot. Motor would only run in 30 to 60 second spurts, if you kept goosing the throttle, and after you got the motor started. It mad all kinds of popping noises and all kinds of racket when attempting to start, and it liked to kill batteries. We would get maybe 5 attempts at getting the motor started before we had to stick the battery charger back on it.

    So because of all this, we decided to tear the motor back down, put it on an engine stand and roll it over and check the clearances. It turns sooooo much better now, I can actually put a wrench on the front and turn it over without to much resistance. Before, that was impossible, I had to put a crowbar through the U-Joint and push and pull with a lot of force to even make the engine turn, damn that was tight.

    If it doesn't run this time I'm taking it all outside and using it for target practice. I think a 30-06 will do some damage to a cast block. It would be like shooting a cinder block, I assume.

    Thanks again.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.
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  11. #9
    Senior Member HKROB's Avatar
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    I say 300hp & 4700 rpm with the Ab impeller.
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    Senior Member ol guy's Avatar
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    I would say more towards the 400 h/p range and I would step on the assembly lube for fire-up. Next is be very careful about your'e oil selection. A 440 chevy likes rpm and will want build power at 4500 to 6000 rpm range. The 427 crank in todays world is a short strock and the 4.311 bore make for high rpm power motor. the best part is the cut on the impellar will work with the combo best of luck to you. M
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    jetboataholic HawaiianJet's Avatar
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    Quote Originally Posted by ol guy View Post
    I would say more towards the 400 h/p range and I would step on the assembly lube for fire-up. Next is be very careful about your'e oil selection. A 440 chevy likes rpm and will want build power at 4500 to 6000 rpm range. The 427 crank in todays world is a short strock and the 4.311 bore make for high rpm power motor. the best part is the cut on the impellar will work with the combo best of luck to you. M
    Thanks.

    I've been told by everyone around here that this is a low RPM engine. But all of you guys are saying it is an average RPM engine. Isn't all of this determined by the cam that is in it, which is a mystery to me. Right now I have Rotella SAE 30 in it for break-in. Then, that is getting drained out and I don't know what to put in it. Syn. or Conv.? What weight? What brand? With me it will probably be some form of Mobil 1. That shit has been great for my little drive about car. It used to burn oil at a rate of about 2 QTs every 2 weeks, but at my last oil change I put Mobil 1 High Mileage in there and I just checked my oil tonight, it was a QT low, but it's been about a month and a half since I topped it off last. So it has cut my oil consumption by more than half. And it's not just me imagining things, I've had all kinds of oils in that little car, I've pretty much tried them all. Some made it slightly better and some made it worse, and the Mobil 1 has just blown me away, that shit produced results. Thanks again.
    HJ

    ***FOR SALE*** 1978 19' Full Stringer Hawaiian Molokai Jet Boat w/ Berkeley 12JC-AB and Chevy 440 Tall Deck ***FOR SALE***

    Quote Originally Posted by mako shark mark View Post
    Oh yeah, Forgot to mention that the hull is a special mixture of speedcote, herculiner and rain-x, all blended together- good for another 8 mph top end.
    Quick reply to this message Reply  

  14. #12
    Senior Member Filucky's Avatar
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    My first jetboat was a 1977 Hornet (just like a Hawaiian) it had a 396 hipo out of a '68 chevell it was rated 325 hp, i added a victor jr intake, holley 850, roller rockers and a slightly bigger cam and when it was all said and done it ran 65mph in a heavy layup v-bottem 19' boat, and according to the impeller charts it was about 350+ hp, but some how this boat out ran a lot of supposed 400-500 hp motors.
    Last edited by Filucky; 04-26-2008 at 11:39 AM.
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  15. #13
    Senior Member ol guy's Avatar
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    Hawaiian jet, I have for 35 years of building and racing boats stuck to one oil. Valvoline racing 40. It has the additives that are being slowly removed from conventional oils and is highly recommended by cam grinders. Im not a fan of the syn oils of today, maybe cause I havent swam in that pool. I know what has worked for me and if its not broke don't fix it. Rotella is also a great oil for break-in, All the protein and minerals a growing body needs. Ran it in my peterbuilt for years.But as I always say opinions are like A$$HOLES everyone has one. LOL M
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  16. #14
    Senior Member ol guy's Avatar
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    Filucky, Horsepower has been misjudged by many for years. In the 70's hardin marine put out in most of the boats they produced a 2-bolt open chamber oval port that was rated at 335 h/p. bigger carb and alittle tuning and bingo 375 h/p. Big blocks need to eat. FEED THE BITCH. M
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