Strip Poker 388

iTrader: (6)

What prop and RPM?

What elevation you at?

Ck the bottom see if there's a hook in it .Mine had one right were the LH motor mount would be .The motor was pulling up on the stringer on that side.

Hot Boat

we need more info like strip said

what is done to the motor. 64 - 65 mph sounds more like a stock 454 mag.

If its a true 550 hp I think you should run some where around 73- 74 mph with the stock X dimension.

if you run the Wong prop on that hull it will ride heavy and scrub speed. Bret at B Blades built me an awesome prop for that hull, that gives bow lift not stern lift like most 4 blade props.

Also the x dimension is very low. around 7 1/2 " I have stern jack and a imco 2" shorter drive. it gives me around 4" higher x when I am trimed up. It was the best $$$ I ever spent on the boat.

Scarab28

Paul - did you ever run the 2" shortie without the setback box. Was wondering what the gains were with each mod.

Again - my '89 excel with the 365 mag only saw 61 at best right off the showroom floor. My friend had a "90 23 foot Nova that did about 63 when also brand new. Even after procharging the 454 with 5 lbs boost, it only did 70 MPH (550+ HP). Now with a procharged 540, it's seeing 80 with std length Imco. Unfortunately I ran 1:36 gears with the imco which I'm sure cost a couple MPH.

that glenn guy

my x dimension is between 8-8.5". i tt ron at imco last week and he figured it should be in the 5.5-6.5" range? im still pretty new to the whole boat thing so i dont know what a "hook" is. the prop im running is a 26 pitch bravo 1 with a bunch of cupping to it that i bought off of ebay for pretty cheap. i replaced a dinged up 24 pitch bravo 1 with it, but ill have the 24 back this week from the prop shop. the 24 ran between 5400-5600 rpms and went 61 on the gps. the 26 only pulls 4400-4600 but pulls the 64-65 on the gps. i still havent quite figured that one out yet. the guy i bought my boat from was actually introduced to me by my race car machinist, who actually built the motor in this boat. its a stroked 454, to a 496. it has factory square port heads that have been cleaned up a bit. it has a single plane intake, an 850 marine holley, and a comp hydraulic roller that is the 2nd from the largest in the marine lineup. the motor is supposed to be in the 9-9.5:1 range with the je flat tops. im geting ready to but an m4, but like i said in my previos reply, i want to make the boat right first. i know my gimbal ring is a bit sloppy, but only on the swivel pin. im getting ready to do hydraulic steering to clean that up though. hope thats enough info to get me in the right direction, and thanks all in advace for any help you can offer!

28SCARAB

Scarab28 Sent you a PM

Strip Poker 388

iTrader: (6)

I also had the 1.36 I belieave it hurt me also

Strip Poker 388

iTrader: (6)

Mine also did around 61-62 new .The first mod I did was Stellings headers dry,merlin heads,ported,MSD,83ocfm Holey carb,1.8 rockers,bobs nose cone,turned a 23 3 blade 5400-5500,speedo said 68 porpoising

Strip Poker 388

iTrader: (6)

Just remember this hull wasnt designed to go very fast.Mine was about 5800lbs. Archer Marine had the same hull which is a 26,no swim platform.A lite race boat ,no inteiror etc.real high X ,Paul Plaff motor, I believe Dan said the best he got was 93mph.

Hot Boat

Glenn guy I am finding it hard ti see that you have 550 hp with your set up.

My 454 with 9:1 compression with supercharger at 6 psi boost only pushed 540 real HP not some over compensated dyno results. A lot of guys can play with the dyno #s and make more hp on paper than what you really have. I am not saying thats your case but from the mods you listed done to your engine it sounds similar to the motor my boat had when I got it. the boat pushed a 22 pitch prop at 5300 and ran around 65-67 if I remember correctly.

I would also try and find a stock 24 p bravo prop in order to get a base line to start with. I would not be using a modified prop until you feel how the boat rides with a stock prop. then talk to a professional like B Blades of Throttle up and tell them how the boat is handling. Bret at b blades made me a bow lifting prop and it's the best prop I ever ran. If my memory is correct ( I might be wrong) I thought that extra cupping in a prop gives you more stern lift , But that hull needs bow lift.

Check your hull for a hook or rocker. Get a 4' straight edge. place it on the bottom of the hull from the transom forward. Starting at the botton start dragging it to the chine and look for inconsistanceies in the hull. if it has an area where it seems to sucked in to the boat , that is a hook. if there is an area that bulges out, then thats a rocker. you should see a small hook at the last 1' from the transom, about 1/8", thats there from the factory. You would like the hull to be as straight as passable. I got a 5' piece of oak hand rail from home depot. I glued sand paper to the flat bottom of the rail and used it as a 5' straight edge to sand the bottom of my hull flat. The boat rode more stable at high speed when I was done.

Hot Boat

I thought the boat was a bit faster that that from the factory with a 454 mag. .

To answer your question , It wasnt that the 2" shorter drive made the boat any faster , in fact it dont even know the before and after #s. What made me keep it was the ride quality. The wife and I borrowed it from a friend to try. We gave it back just before a poker run.....Very Bad Move.... The ride was so much better with the shorter drive that my wife practically demanded that I get it back when we finished the run.


I will be sure to get all the speed #s with the new motor next season. I want 86 +