Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

[Marina Bay]

Can any body help me with an answer to replace my dead mercruiser 5.7 with 7.4L engine with new transom and outdrive?

I got a good deal on the 7.4L but worried that it wont fit inside my Cabrio 244 Larson.

Please advise.

 

[Bamaman1]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

You didn't say if you were satisfied with your old small block motor, but I'd probably suggest repowering it with another 5.7 motor.

The big blocks are much more thirsty, and fuel mileage is very important now. But future gasoline prices might make your new boat "a floater" if you cannot afford to feed that monster.

 

[theBrownskull]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

I don't know if you could maybe someone with more knowledge with that type of boat knows. First I would see what the max hp is for that boat and lower unit is and go from there. If it was me I would replace it with a new 5.7 or 6.0 or something like that.

 

[Bondo]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

Can any body help me with an answer to replace my dead mercruiser 5.7 with 7.4L engine with new transom and outdrive?

I got a good deal on the 7.4L but worried that it wont fit inside my Cabrio 244 Larson.

Please advise.

Ayuh,... Assumin' you've now got a 350/ Alpha 1,...

Ya it can probably be done, but at a Pulleys to Prop swap, with the Bravo drive...

 

[04fxdwgi]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

If you have an Alpha, then I believe max HP is 300. The 7.4 will put out more than that, so a Bravo is more compatable, with it's higher HP rating. The 7.4 also likes a 1.5:1 gear ratio. Other than that, the bell housing should bolt right up and the front motor mounts will be very close in terms of location also. SB to BB Chevy transplants are very common and quite easy in the hot rod world. But there are a TON of other things that need changing, too. Just do your homework. Also consider the 7.4 is HEAVY and considerably wider than the 5.7...... and may be an issue if your engine compartment is super tight, but there are a ton of 24' boats w/ the 7.4 in them. Looking at some pics of 244's, looks like the 7.4 would fit, no problem, but that seat "hatch" access would all but eliminate any chance of getting into the engine hole to work on that big wide 7.4.

SB Chevy's in the 6.8L class can put out the same / more HP and torque than a 7.4 if done right and would be a direct replacement for the 5.7, dimension wise.

(PS: I have a 7.4 and love the thing )

 

[Marina Bay]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

Thank you all for your comments,

The reason why I want to replace is that my 5.7L seized and I got a great offer to buy 7.4L, my only concern is the space inside the engine room whether the engine base will fit or not? going more on width it is ok as the sides of the engine room is empty.

Can any body with expert tell me if I can do it easly or need some alterations.

Thanks

 

[Bondo]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

Thank you all for your comments,

The reason why I want to replace is that my 5.7L seized and I got a great offer to buy 7.4L, my only concern is the space inside the engine room whether the engine base will fit or not? going more on width it is ok as the sides of the engine room is empty.

Can any body with expert tell me if I can do it easly or need some alterations.

Thanks

Ayuh,... What Drive,..??

Easily isn't the same to You, as it is to Me... Of Course, there'll be some modifications needed...

 

[Marina Bay]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

The Drive is Bravo 2 or 3 not sure, but the engine is to be sold with the outdrive and transom.

 

[Bondo]

Re: Can I replace MErcruiser 5.7 engine with 7.4L to my 24 feet

The Drive is Bravo 2 or 3 not sure, but the engine is to be sold with the outdrive and transom.

Ayuh,.... Ya don't say what the vintage of the hull, 'n old drive is,...
So,...
At worst, you'll be drillin' a couple of holes, 'n maybe tunin' the keyhole with a grinder, 'n resealin' the transom,...

It ain't a Major refit swap at all,...
I loaned my installation manuals out, but I believe yer only talkin' an inch or two, here or there...

Just basic fiberglassin', 'n mechanicin' skills used...
Dependin' on the motorbox, I'd probably call it an Easy swap...