3.7L repower, what are my options

[knied1]

I currently have a 3.7L i would like to re-power the boat. Im thinking about a 4.3, but does anyone know if i need to upgrade the outdrive as well.

What other things do i need to look into before i make a decision on a powerplant. I use the boat in the Great lakes, so i do not need the closed cooling system.

Thanks

 

[tschmidty]

Re: 3.7L repower, what are my options

3.7 is a 4 cylinder, 4.3 is a v6, not an easy or worthwhile swap. Don't need to upgrade the outdrive exactly, but I believe the gear ratio is different. Really not a worthwhile thing to do honestly. Just look for a good used boat with a 4.3 already.

 

[knied1]

Re: 3.7L repower, what are my options

my boat is in great condition, and only a 40 gal tank, buying a different boat will be no more than picking up another persons problems.

I want a little more power, and i would just like to get away from the regular maintenance of the 470 wich is alot more than other motors, the upgrade would be worth it to me, plus going from a 4 cyl to a 6 cyl should geive me a little more out of the hole than what the 4 cyl does.

 

[robjen1019]

Re: 3.7L repower, what are my options

My advice if you really want to do this is to find a donor boat. that way you can do a transplant. Really helps when measuring for stringers.

 

[nola mike]

Re: 3.7L repower, what are my options

my boat is in great condition, and only a 40 gal tank, buying a different boat will be no more than picking up another persons problems.

I want a little more power, and i would just like to get away from the regular maintenance of the 470 wich is alot more than other motors, the upgrade would be worth it to me, plus going from a 4 cyl to a 6 cyl should geive me a little more out of the hole than what the 4 cyl does.

depending on the year of your 4.3, you might not get that much more power (iirc, 175 hp on a carbed engine)--plus heavier. if there's nothing wrong with the 3.7, probably not worth it; from what i've read, you'll need to modify the stringers. outdrive ratio is the same. what maintenance does the 470 require that the 4.3 doesn't?

 

[stonyloam]

Re: 3.7L repower, what are my options

I want a little more power, and i would just like to get away from the regular maintenance of the 470 wich is alot more than other motors, the upgrade would be worth it to me, plus going from a 4 cyl to a 6 cyl should geive me a little more out of the hole than what the 4 cyl does.

You will be adding about 200 pounds to the stern of the boat with a V6, the outdrive ratio would be the same. As for power, a little more is what you will be getting. What makes you think a seawater cooled motor is going to require less regular maintenance than a 470? Proper winterizing of a 470 is WAY easier than a seawater cooled engine, just look at all of the cracked block posts here. If you didn't winterize a 470 at all you would probably only be out $400 for a heat exchanger, not the $2500 engine. How much money do you want to put into a 20+ year old boat. I looked into it myself a while back, and concluded that it was way too much time and money to be worthwhile. Anyway, just my opinion, and you know what they are like.