Adding 100+hp. Would you re-prop ?

[QBhoy]

Oh trust me when I say... a big block is always the way to go.
I learned that 30+ years ago when I was building drag cars.
My last one was 632 cubic inches.

I’d say the hull you put an engine in, is just as or more important perhaps. I don’t think your hull will have the ability to push through a certain barrier perhaps

 

[QBhoy]

Ouch - Bon Jovi - shot thru the heart

"Shakey finger" - at ya

My 95 Rinker is a bit lighter but it was pulling 4 solemn ski's up all the time, even pulled 9 at one time, but the other 4 were knee boards and twin ski

At any rate, my 300hp 454 gets me to 60mph



You tell Em

Haha. Sorry AD…no offence intended there. I take it back !

 

[Meames1]

remember, your drive is limited to 5500 RPM or less. Circle track motors spin to 11k. the XM270 is a small cam compared to what is normally in a circle track motor. it has almost no overlap and runs out of breath at 5300 RPM

LOL

 

[apw30534]

I’d say the hull you put an engine in, is just as or more important perhaps. I don’t think your hull will have the ability to push through a certain barrier perhaps

I can't (won't) argue that at all... but suffice to ay, I'm not interested in pushing or approaching any hull barriers. My wife already complains about the wind in her face when we are over 30mph. lol
The current combo runs 48mph... so if I can occasionally get into the upper 50's low 60's I'll be fine with that. I think with 350+hp and previous feedback/input from others with a similar hull/powertrain, it is achievable.
Obviously the proof is in the pudding. I will be sure to update this thread or start a new one when I have it together, running and tested. If I fail or have disappointing results, I am man enough to admit it and will go back to the drawing board. (Big Block) lol

 

[apw30534]

Finally got the cylinder heads back from the machine shop yesterday. They have been there since January.
Now I can start making some progress.

 

[apw30534]

Also got better data...
I installed a new Garmin GPS a couple weeks ago and on a brief test run... saw that the speedo is WAY off.
Last time out... loaded a bit heavy with 75gallons of gas and a 225lb friend.
Dash showed 48mph / 4500RPM
GPS said I was going exactly 42.0mph.

So... I think the 26pitch props will stay on with the new motor. The new motor will run to 5500RPM... so it might be a decent combo.

 

[apw30534]

Well it runs.

 

[harmanoff]

nice!! love the sound of those boats that have the engines like that, got a buddy who has a Sacrab, dual exhaust, nor sure the engine it in, but just listening to that thing idle is awesome lol. He tops out at around 64 MPH so maybe a 454? not sure

 

[Blorton]

I'd sure like a 454 in my 18' bowrider.

 

[apw30534]

nice!! love the sound of those boats that have the engines like that, got a buddy who has a Sacrab, dual exhaust, nor sure the engine it in, but just listening to that thing idle is awesome lol. He tops out at around 64 MPH so maybe a 454? not sure

Nah, just a little 355 with Vortec heads and comp cams xm270 hydraulic roller.

 

[apw30534]

Just got my aluminum manifolds and stainless risers yesterday to mock-up the assembly.
Should be a bit of an improvement (and alot less weight) over the stock Mercruiser iron.

 

[apw30534]

I'd sure like a 454 in my 18' bowrider.

If I had known ahead of time the direction I wanted to take this 24' bowrider... I would have opted to build a big block instead. Probably a 496-540 cube combo.
There is just no comparison.

 

[Blorton]

Speaking of cool sounds, being far from the coast, my exposure to offshore racing boats has been very limited. I stumbled across a great youtube channel that has good mics on their cameras, and the sound of some of those cigarettes rumbling through the home theater is awesome.

 

[Scott Danforth]

Just got my aluminum manifolds and stainless risers yesterday to mock-up the assembly.
Should be a bit of an improvement (and alot less weight) over the stock Mercruiser iron.

keep anodes on hand.

 

[jimmbo]

Just got my aluminum manifolds and stainless risers yesterday to mock-up the assembly.
Should be a bit of an improvement (and alot less weight) over the stock Mercruiser iron.

Is the new Manifold, one that is designed for a Marine Engine? Edelbrock makes Marine Intakes that have the Water Passages lined with Bronze, to reduce Galvanic Corrosion, and the resulting disappearance/dissolving of the Manifold

 

[apw30534]

Is the new Manifold, one that is designed for a Marine Engine? Edelbrock makes Marine Intakes that have the Water Passages lined with Bronze, to reduce Galvanic Corrosion, and the resulting disappearance/dissolving of the Manifold

This is a lake only boat... but regardless of that... the next big purchase will be a fully closed cooling system.
The engine and manifolds will only get antifreeze run through them. Any water from under the boat (fresh or salt) will only run through the heat exchanger and discharge out the stainless risers.

 

[Scott Danforth]

Add the HX before the motor hits the water (any water).

the debris that the leg picks up, sits in the bottom of the block until you put an HX on it. then it plugs up the HX on the side you cant clean

 

[jimmbo]

With a Closed Cooling System you can use a higher temp Stat, which will reduce engine wear, but on the negative side, raise the temp in the Engine compartment, which will drop the HP a bit

 

[apw30534]

Latest update just to close out this story...
Sold the boat and the spare engine about 2 weeks ago.
Currently shopping for a 2007-2008 Chaparral 236, 256 or 276ssx with a 496 in it.
No more small block stuff for me. Big Blocks only from this point on.

 

[jimmbo]

A boat in that size range, will respond much better with the Larger Displacement, and get on plane and be a 1/4 mile down the Lake, while the SB is still raising the Bow.