mcollinstn

Knock sensor isn't necessary on a low boost application.
And the one shown is intended to be used on newer motors.

Blowers will definitely provide a lot of bang for the buck.
But in that boat, I feel there's a need for 540's.

He's already got the 454's though, so blowers is the only suitable option unless he plans to swap motors.

5 pounds of boost (roots or whipple), good head gaskets, and a mild blower cam. He'll probably need to upgrade his fuel lines and filter to handle the increased fuel flow. And then he'll be set.

Crazyhorse

The Eagles were equipped with 3/8 fuel pickups and lines, so he should be alright provided the engines stay aroung 600 horsepower. Still, the boat won't be a rocket ship and he can expect a top speed of 60 with reliability.

electrical1

thanks for all the advice. The whipple I think will be a problem because of height. As far as exhaust I'm running stainless 4" headers. with holley 800 carbs. This may sound stupid but Is there a super charger that will mount to the front of the motor and not on top or something that is just as good that will mount to the front.
As far as speed I know the boat will never win any races, its way to heavy 60's would be great. the 540's sound good but I'd hate to waste that kind of money then tear it down to set it up for blowers. as far as drives I know the drives probally won't last they are TRS drives. I'll cross that bridge later.

formula31

Dont poopoo those trs's. They will handle "heavy" much better than Bravo's.

Mudball

Why did Merc stop making the TRS's?

formula31

Most manufacturers, including the one I work for, want to market "new" stuff as aften as possible. Im sure that was one reason. I think the boat manufacturers had something to do with it too. I can imagine that they wanted rid of the transmissions so they could move the engines back for speed and room and cost. I think the Bravo profile may be faster than the trs profile too but maybe the weight moving back played more of a part there. There were "good" and "bad" Trs's and well as Bravos but overall I think the trs would take more torque and punishment from what Ive seen. Hopefully some of the merc guys will chime in their opinion

Edward R. Cozzi

Every time I read a formula31 post my respect for his knowledge increases.

Sell those 454s and get some tall-decks. 540, 572 cu. in. with a single Dominator.

You have minimum down-time, good performance, decent economy and longevity.

The blowers will not only be expensive, but will shorten the life of any boat that heavy.

Keep the cubes big and the rest of the engine simple and you'll be far happier in the long run.

Edward R. Cozzi

Oh yes, I just thought of something else!

If down the road you decide to upgrade the power, you have a much better base engine to work with.

mcollinstn

Prochargers or Vortechs will mount off to the side and will not increase the height of your installation. But they are not the best option for a really heavy, marginally underpowered boat. They only make a pound or so of boost in the rpm range where you will be trying to get on plane. On this large heavy boat, I don't feel that will be suitable.

There are sidedraft carb options for roots blowers, but I can't recommend them for marine apps.

I believe Whipple makes a low profile carb adaptor that mounts the carb behind the blower. Might be an option.

Before you rule out a roots blower (cheapest and easiest), remove your flame arrestor from the carb and measure the actual amount of space you have for a taller intake system.

electrical1

thank you all for your advice. still not sure what way to go. so lets throw this in the air. MOST OF YOU HAVE MORE EXPERIENCE THAN I DO WITH MOTORS. SO HERE IS THE QUESTION. YOU WANT TO SPEND NO MORE THAN 30000.00. YOU NEED 2 MOTORS, THE MOST IMPORTANT THING IS RELIABLE AND STRONG, DO NOT WANT TO DO THIS AGAIN FOR A FEW YEARS, YOU WANT TO GO AS FAST AS POSSIBLE, BUT DON'T WANT TO BE ON THE EDGE OF BLOWING UP. YOU HAVE 2 BRAND NEW 454'S HO'S WITH 420 HP THAT HAD OIL STARVING PROBLEMS WITH SLIGHT DAMAGE.WHERE ONLY RUN FOR 30 TO 40 MINUTUES. WHICH WAY DO YOU GO. REBUILD STRONGER OR BUY SOMETHING BIGGER AND NEW. I LIVE IN RI SO IF THERE IS SOMEONE NEAR BY WHO CAN HELP LET ME KNOW THANKS