Omc to mercruiser

[sw33ttooth]

so i've finnaly got fed up with my dam OMC no one knows why it wont run over 4k rpm and i figure over the course of winter i could watch craigslist and buy a farely decent set up.

right now i have a ford 5.8l 351 and a cobra outdrive, 23 foot cuddy.

i would really love to go to a 454 and bravo one if at all possible, but i need to know what exactly i am looking for in the cross over and will all 1990+ 454's fit all the bravo ones?
will the bravo outdrive even fit in the cobra transome? i've heard alpha's you need to drill 2 new holes then it fits in the same also is a 454 any bigger then my 351, length or width wise?

any imput would be greatly appretiated

 

[HT32BSX115]

Re: Omc to mercruiser

so i've finnaly got fed up with my dam OMC no one knows why it wont run over 4k rpm and i figure over the course of winter i could watch craigslist and buy a farely decent set up.

right now i have a ford 5.8l 351 and a cobra outdrive, 23 foot cuddy.

i would really love to go to a 454 and bravo one if at all possible, but i need to know what exactly i am looking for in the cross over and will all 1990+ 454's fit all the bravo ones?
will the bravo outdrive even fit in the cobra transome? i've heard alpha's you need to drill 2 new holes then it fits in the same also is a 454 any bigger then my 351, length or width wise?

any imput would be greatly appretiated

Howdy,


You have made a GOOD choice!!

A few years ago I pulled my OMG 460 King Kobra and replaced it with a 1997 454/Bravo III. The difference was exhilarating to say the least!!

Although the cut-out is the "same", you WILL have to drill 2 additional holes for the 2 "extra" studs on the bravo gimbal mount AND of course re-"do" your side engine mounts.

While your at it, inspect your transom and entire engine compartment, stringers etc, carefully for water intrusion.

I bought the entire engine/drive/transom/harness/trim pump etc, from a (wind damaged) '98 24' Bayliner from the original owner it had about 120hrs on it since new and was never used in salt!

It was a "swinging" deal!!

I also found for sale locally a 2003 300hp 5.7L MPI Bravo I, and a 2004 MAG 496 Bravo III but I had already bought the one I have.

The installation went with no real problems at all. Drilling the 2 additional holes was pretty easy even though I didn't have a jig (it would have been easier with a drilling-jig)

What's the boat that it's going in? A 23' boat will benefit from a Bravo III . I lost a little in top end....maybe 3-5 mph but it just ROCKETS out of the hole now. My brother bought this boat new and it ALWAYS was a DOG out of the hole even when it was new.....


Regards,


Rick

 

[Bondo]

Re: Omc to mercruiser

so i've finnaly got fed up with my dam OMC no one knows why it wont run over 4k rpm and i figure over the course of winter i could watch craigslist and buy a farely decent set up.

right now i have a ford 5.8l 351 and a cobra outdrive, 23 foot cuddy.

i would really love to go to a 454 and bravo one if at all possible, but i need to know what exactly i am looking for in the cross over and will all 1990+ 454's fit all the bravo ones?
will the bravo outdrive even fit in the cobra transome? i've heard alpha's you need to drill 2 new holes then it fits in the same also is a 454 any bigger then my 351, length or width wise?

any imput would be greatly appretiated

Ayuh,... It's a pretty easy swap out,...
The only way to do it, is buy a runnin' donor boat with the driveline ya want, 'n junk it out...
That way ya get ALL the little pieces that add up Quickly...

The transom interface is pretty standard, other than a hole or 2, or some Tunin' with a grinder...

 

[sw33ttooth]

Re: Omc to mercruiser

thanks rick the hull is a 1991 four winns sundowner 225. with the 5.8l i have done as fast as 42 with the paddle wheel from the fish finder, lately seems it will only do about 38mph. i was hopeing with the bigger engine i could pound out more speed, maybe its just the heavy hull that wont make it go. i figured i'd either get a steel on the engine or outdrive after winter damage and work it from there but if i could get a set up from a damaged hull that'd be even better. also i do things the easy way i have acess to a front end loader and 2 hi-lo's and some air tools so the swap wouldnt be but a saturday chore maybe into sunday if i start drinking early

by the way whats the real differnces between the bravo's? i dont really want the duel prop as i've heard those are $1400 on up and if i gota change pitch from the past owner to my hull that will be 1/3rd of the expense.

 

[HT32BSX115]

Re: Omc to mercruiser

by the way whats the real differnces between the bravo's? i dont really want the duel prop as i've heard those are $1400 on up and if i gota change pitch from the past owner to my hull that will be 1/3rd of the expense.

Having a Bravo III is like having twins. You get far better low end thrust. the low (idle) speed handling is much improved too.

In a boat that size the improvement is significant.

With a 454 you would probably want to find a 1.81:1 drive and use 24p props.

I see them on ebay for about $600 and lower all the time (they're the most common) ........ and cheaper in winter time.

You won't be dissatisfied with the performance.


Cheers,

Rick