4.3 mercruiser vs. 302

I am beginning the process of repowering my '83 Crestliner Nordic 19 and have 2 donor options currently. One is a 1991 4.3l mercruiser and the other is a "new(less than 100 hours) long block 302-188 hp" which I am trying to get more info on. I think both of these have plenty of hp to replace my OMC 3.8l v6 but wondering if there are any opinions as to which is a "better" choice. I have already purchased an Alpha 1 outdrive which I think is compatible with either option. Just wondering about weight, space, mileage and any other input out there. Thanks.

Re: 4.3 mercruiser vs. 302

retroinmpls said:

I am beginning the process of repowering my '83 Crestliner Nordic 19 and have 2 donor options currently. One is a 1991 4.3l mercruiser and the other is a "new(less than 100 hours) long block 302-188 hp" which I am trying to get more info on. I think both of these have plenty of hp to replace my OMC 3.8l v6 but wondering if there are any opinions as to which is a "better" choice. I have already purchased an Alpha 1 outdrive which I think is compatible with either option. Just wondering about weight, space, mileage and any other input out there. Thanks.

Click to expand...

Ayuh,.... Welcome Aboard,.... Unfortunately, that's Not true,...

There's no Ford flywheel covers to fit the Alpha transom, ya need an ole MC-1,...

Re: 4.3 mercruiser vs. 302

In general there will be more parts and options with the 4.3. Fuel difference is probably not worth counting. Merc hasn't used Ford's in years and for that reason alone, familiarity favors the 4.3.

1.47 with a 4.3l?

1.47 with a 4.3l?

Thanks in advance for any input on this topic-this forum is incredible! I have a 19' Crestliner Nordic that I am repowering and need some advice regarding not only the engine but the sterndrive as well. I got a super deal on an Alpha one outdrive but find that the gear ratio is 1.47- intended for the 5.7l engine apparently. The two engines I am considering are the 4.3l v6 because it is close to what I have (3.8 OMC) and seems reliable and easy to get parts, and a 302 v8 because it is near new and the donor boat has other things I could use. Both are priced the same and I am seeking advice on which to use on a different thread but my question is this... is it going to be problematic using the 1.47 drive with either of these or should I stick with the drives that come with them. I should mention that my boat is aluminum and fairly light (around 2000 lbs) so even with the current 3.8l it has virtually no hole shot and hits 37mph at wot which is plenty fast for my purposes, although extra never hurts I guess. Is there a prop setup that would help me out here? Current prop is 14.5 x 17 and the new outdrive has a 15.25 x 15. I don't have to use this drive but it is brand new so if there is a way I would be willing to explore those options. Thanks.

Re: 4.3 mercruiser vs. 302

Ayuh,.... Lets keep all this in 1 thread,.... Ok,..??

The 1.47:1 drive won't work with the 4.3l,....

It'd run Ok against the 302, but you'll still have the fitment issues I talked 'bout above,...

Re: 4.3 mercruiser vs. 302

you can not be looking at price alone.

as Bondo mentioned, the 1.47:1 will not work with the 4.3 and the Ford 302 will only bolt to a very specific MC-1 flywheel housing



not to mention, you have an OMC 3.8 which is probably in front of a stringer.

you will need to rebuild your transom because the OMC stringer hole is about 3 x the size of everything else.

now if you want to keep your existing stringer outdrive, then I would go with the 4.3 and find the elusive aftermarket coupler for a 1-piece crank or have your existing coupler re-machined.

Re: 4.3 mercruiser vs. 302

Seems you have chosen the wrong fork in the road.
These guys will get you on the right track.

Re: 4.3 mercruiser vs. 302

steelespike said:

Seems you have chosen the wrong fork in the road.
These guys will get you on the right track.

Click to expand...

I have been following the forum for a while regarding the OMC retrofit so I'm up to speed on that issue. Discovering a repaired exhaust manifold in our new to us boat led me down the road to where we are now. My wife and I decided that we really like the hull/setup on the boat and since everything currently works that we would use it until it didn't and in the meantime start looking for repowering options-namely donor boats per the recommendations we found on the forum. I'm not too intimidated by the transom reworking and have looked at some of the same model that came with Merc drives and I know I can do at least as good as those and almost certainly better. Glad to hear about the 4.3 because that was what I have been looking at using but that 302 popped up and it threw me for a second guessing loop. I'm a sucker for a good deal (as evidenced by the drive purchase) I guess but I shouldn't have much problem moving that down the road. I will move ahead with the purchase of the 4.3 donor boat this weekend and thanks much for the input, you have provided a ton more info through previous threads than you know! More to come I'm sure.

Re: 4.3 mercruiser vs. 302

I have to disagree here...... No reason in the world that the 1.5 (1.47 same thing) wouldn't work with a 4.3 ESPECIALLY in such a light boat.... my 20' arrowglass cuddy with a merc 898 (198 hp 305) came with a 1.5 and ran great... the 4.3 has very close to the same power and will be in a much lighter hull.. he'll probably run a 19 pitch prop MAYBE even a 21 and will have a rocket of a boat compared to his old 3.8

I have done quite a bit of engine and drive swapping btw including putting a both 1.5:1 and 2:1 alpha's with various props behind a straight 6 in a 26' flybridge cruiser. in the cruiser the 2:1 got me the same top speed but a better holeshot and cruise but that was a 6000 lb boat... with your little tinny the 1.5 will be a fine match.


Don't even consider the ford motor.... A ford mercruiser is about as good of an idea as an nash rambler for a daily driver... just don't do it.

Re: 4.3 mercruiser vs. 302

4.3 is best by far.