Engine upgrade.

[mkfs9]

I have a searay seville 18"8 with a mercruiser 4.3L V6 175HP Alpha one set up. However I am wanting some more performance out of the boat. I am already running a 21 laser 2 and hitting 4500RPM, and i dont think it would pull a 23.

That was the largest engine option i could have when i purchased the boat but could i put the 5.0 V8 block in or would it not fit?

Many thanks

 

[180shabah]

Re: Engine upgrade.

Tell us a little mpre about your engine.
What year is it (SN would be even better)
Is it a 2 or 4 barrrel carb??

 

[Reel Poor]

Re: Engine upgrade.

Sure it can be done. Time and money can make just about anything work, but a boat that size has a Max HP decale on it somewhere. If you were to have an accident after making modifications the Coast Guard, your/their insurance company, and an ambulance chasing lawyer may make you regret it.

 

[mkfs9]

Re: Engine upgrade.

I didnt know about the HP decale on the boat but i will check it out thankyou. What would a usual HP limit for a sports boat like this be?

Its the second block ive had in the boat, my first 4.3 had a bad oil blow, 5 years back, and i had a new block fitted straight after (same as original). The boat is a 1989 searay seville, with the 4.3L 175HP 2brl carb, alpha one leg.

Sorry a cant quote SN at this moment.

Many thanks

 

[180shabah]

Re: Engine upgrade.

The 4.3 is a better foundation to build on than the 305, it just isn't as smooth. I would upgrade to a 4bbl which will put you right in the neighborhood of 200hp, Vortec heads are worth another 25hp or so and if you only boat in fresh water or have Fresh water cooling then an aluminum aftermarket Intake would be worth a few more HP and usually costs less than the factory manifold. All of this can be done without removing the engine and will not adversly affect reliability.

AND - a big plus in a boat your size, it will weigh about 100 pounds less than the V8.

 

[Bondo]

Re: Engine upgrade.

Sure it can be done. Time and money can make just about anything work,

Ayuh,..........

I'd say Alittle Imagination,+ Alot of Money would do it....................

Last year,..... We gutted a mid-late 70s SS-19 Slickcraft of it's 2.5l, mod.1.......
And stuffed in a 350 MPI, Alpha Gen.II.........

The result is a 30-odd year old Wet Corvette......... My Boss's 2nd Childhood.........

 

[180shabah]

Re: Engine upgrade.

a boat that size has a Max HP decale on it somewhere.

I thought they only stipulated max power for OB powered boats.