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-   -   big cubic inch motors (https://www.offshoreonly.com/forums/fountain/166013-big-cubic-inch-motors.html)

bcfountain 08-13-2007 11:23 AM

big cubic inch motors
 
any of you fountain guys have any thoughts on big cubic motors?thinking about building a 572,or a 605 motor.i have a 502mpi now....great gas millage,just want something w/more snap.how do big engines fair on marine applacations?are they reliable?are they big and thristy?i know speed cost.....how fast do ya want to go...right.just looking around for the all the way around package.thanks.

Rebel_Heart 08-13-2007 12:02 PM

You can easily turn those 502s into 540s. I had a dart block in my 27 that was 572. Currently, have 540s. They both dynoed about the same. You will definitely lose efficiency, but then again you can't compare the power gains.

gofastlvr 08-13-2007 01:21 PM

"there is no replacement for displacement"

Beak Boater 08-13-2007 07:37 PM

If you are looking for seat of the pants acceleration, theirs nothing like blowers. Big cubic in. is nice, but smaller 540, with 7 lbs of boost, especially Whipple, or Prochargers, make up for alot of cubic inches. Had 540's with Whipples, had 572's with 1071 BDS blowers. If they are set up right, they can be as reliable as big cube n/a motors. Its a matter of preference. They are all had on Bravo drives:D

fountainguy214 08-13-2007 09:07 PM

id say a 502 block with 420 b&m blowers that is what i have on imcos in a fountain

jeff1000man 08-13-2007 09:11 PM


Originally Posted by gofastlvr (Post 2232807)
"there is no replacement for displacement"

YES, YES, and YES

jeff1000man 08-13-2007 09:16 PM

I have a set of 9.8 deck 582's. They are friggin awesome.

I don't have them built to their potential at all. You can easily make an 850hp na engine with those.

I even idle mine at around 600-700 rpms at the dock in gear.

Mine are set up and dynoed at 600 at 4500.

If you don't like blowers. Tunnel rams work really well in big cubic inch engines.

Talk to Scott at Dyno Flo. He is very helpful and you can't beat his pricing.

tblrklakemo 08-13-2007 09:30 PM

first things first......getcha some serious drives so you can take advantage of the newfound power.

jeff1000man 08-13-2007 09:37 PM


Originally Posted by tblrklakemo (Post 2233685)
first things first......getcha some serious drives so you can take advantage of the newfound power.

Underprop them a litle and let them spin. Take it easy out of the whole.

We have a guy here running a 36' cat with 900+ engines with stock old style Bravo's.

His trick is to let them slip a little. He stopped having luck above 6800 rpm's becasue of bad harmonics, but he does real good with them under or right at 6000.

The key is he has a lot of extra power that he doesn't use.

GCAT911 08-14-2007 02:17 PM

stop fooling around and go T U R B I N epower.:party-smiley-048:


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