Is this the aluminum head 470.

[Rranger]

There is a 3l out there I can grab, involves a day drive and $1500 Canadian 500 hours on it blah blah. Would get a comp test first. Guy can run it to. Last question and I did google this with no luck is what’s the difference in Hp between the 2.5 and the 3. I can’t find anything on it.

 

[Scott Danforth]

There is a 3l out there I can grab, involves a day drive and $1500 Canadian 500 hours on it blah blah. Would get a comp test first. Guy can run it to. Last question and I did google this with no luck is what’s the difference in Hp between the 2.5 and the 3. I can’t find anything on it.

the 2.5 was anywhere between 90hp on the low end and 120hp on the high end
the 3.0 is between 115hp on the low end and 160hp with EFI

carbureted, most were 140hp.

 

[Rranger]

Thanks for your help Scott much appreciated.

 

[Scott Danforth]

BTW, with minimal work, you can get 160hp out of a 3.0..... then again, with a fair amount of work you can get 200hp out of the 3.7.

 

[QBhoy]

O

Get a 3.0 and lose 40 hp. What's the upside?

Where you get the 40hp I don’t know. Even if it was perfect.
thw upside is that your family will actually enjoy boating...if the boat is reliable and not getting towed back by your friends. You keep those friends too.

 

[QBhoy]

I appreciate the input. 4' hx size? Is that Exhaust manifold? And a 470 has 40 more HP than the 3L? And this is what I'd likely be replacing.

It doesn’t have 40 more horsepower at all.

 

[nola mike]

It doesn’t have 40 more horsepower at all.

No? How much?

 

[nola mike]

what is shown is an old 2.5 liter.

Suggest you replace with a 3.0

Agreed, you'll still get a performance boost over what you have.

 

[QBhoy]

No? How much?

Most recent 3.0 are 140hp at prop. 470 was a maximum 170 at flywheel as far as I know. Even if it was at best at prop. That’s only 30. I’m not having a go. Speaking from a horrendous experience and many many ruined days out. Rebuild the thing twice and he eventually gave in. Dropped a 3.0 straight in. Direct fit onto same existing patterns. Honestly...there was very very little difference in performance. That was with the same prop. Was like perhaps a second or two slower to plane..and the top end was identical as far as we could tell. That was on a 21ft cruiser. Still did over 30 mph. Just trying to save a lot of pain.

 

[Rick Stephens]

A 470 has a nice torque increase over the 3.0L... but, the known shortcomings would make me more than wary. Boats are already expensive and hard to find parts for. The 470 is at minimum a big learning curve to make run and keep running. Cannot recommend it, especially one with unknown issues.

 

[nola mike]

There's no such thing as a reliable 30 year boat with an unknown history.

 

[Rranger]

Well I’m leaning towards the 3l after all the advice on here. Is the trim tilt off the 2.5 assuming it works any use as a backup for the one that will come with the 3l?

 

[Rranger]

Would a 3L bolt up to this 2.5 drive and intermediate housing?

 

[Scott Danforth]

Would a 3L bolt up to this 2.5 drive and intermediate housing?

yes, technically the drive will bolt up after you swap the motor (drive has to come off to pull the motor)