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Random Quote: never argue with idiots, they drag you down to their level and beat you with experience
I own a 233, 1972 formula. The v8 in it is siezed and a good friend of mine gave me a Complete merc 4.3L 220hp that he pulled out of a boat at his boat yard. The V8 that was in it was rated for 260 HP, and the new v6 rated for 220HP. Just wondering if anyone has any rough idea of the performance loss i will have from the reverse swap? My quess is 6-8 knots off the top end and probably alittle better on gas if i keep my foot/hand out of it? Gas prices are a huge consideration on this swap. I am more into fishing than performance, so as long as i can get the boat on plane and do atleast 20kts, save alittle on fuel consumption, then im happy.
Also if anyone has some Prop selection advice since the Outdrive gear ratio is still geared for the V8. I Ran a 14-1/2 x19 with the V8 w/ 1.5 drive gear ratio. Figured a 15''pitch prop might do the trick for the V6?
Here she is, and yes she does need bottom paint before the season
I doubt you'll see much if any fuel savings from the swap. You'll see a bigger improvement if going from an old style 350 to a vortec 350 V8 probably. I don't think the performance numbers were that good on that boat with the straight 6 factory option. The V6 would probably be close to the origanal 302's that came in them.
those old formula deep vees are great boats - hence the term heavy deep vee ,they need power to perform and Im not talkin about being a speed demon. some off those boats came standard with the 225 omc sterdrive or the mercruiser 260 . actually you may burn more fuel as the 6cyl will have to work harder. I understand a free engine is a free engine but I would consider trading for a v-8 if it dosnt hurt your friends feelings
Well i think im still going to try it. It looks like a really easy engine swap, see what it does i quess. If its to much of a dog ill take her out and rebuild the 350. wtf why not, you live and you learn, maybe turn out to be a decent swap, maybe ill eat my words......
__________________ B.O.A.T - Break out another thousand
I hope it works out for ya ! letus know and by the way thats a nice looking original formula , nice hard top as well as it matches the lines of the boat
Horsepower is simply torqueXrpm/5252. It has a higher "horsepower" rating because it produces its peak at a higher rpm. I've got the same hull..blackfin.. with 2-302's.
the old blackfin hull is the same as the 233 formula? for some reason the last time i looked at one i couldn't find the same lines.... i need to look again
__________________ B.O.A.T - Break out another thousand
Ok found it, 24' blackfin is the same hull... ok i was lookin at the 25's
what i really want to do is take my 233, and put a big block right in the middle of her.. straight inboard
I own a 233, 1972 formula. The v8 in it is siezed and a good friend of mine gave me a Complete merc 4.3L 220hp that he pulled out of a boat at his boat yard. The V8 that was in it was rated for 260 HP, and the new v6 rated for 220HP. Just wondering if anyone has any rough idea of the performance loss i will have from the reverse swap? My quess is 6-8 knots off the top end and probably alittle better on gas if i keep my foot/hand out of it? Gas prices are a huge consideration on this swap. I am more into fishing than performance, so as long as i can get the boat on plane and do atleast 20kts, save alittle on fuel consumption, then im happy.
Also if anyone has some Prop selection advice since the Outdrive gear ratio is still geared for the V8. I Ran a 14-1/2 x19 with the V8 w/ 1.5 drive gear ratio. Figured a 15''pitch prop might do the trick for the V6?
Here she is, and yes she does need bottom paint before the season
I have a similar motor in a 1988 Four Winns 20', it weighs in at about 3000 lbs. With the 4bbl carb it is fine for this boat but I think it'd be underpowered in a 23 footer with a deep V hull. That's a beautiful old classic that deserves a proper V-8. Don't forget if you swap in the V-6 you will have to re-do the engine mount pads for the front mounts as the front mounts on a V-6 are several inches back from those on a V-8.
__________________ 1988 Four Winns 200 Horizon
4.3 OMC Cobra
1998 Jeep Grand Cherokee
4.0/NV 242 Selectrac
2007 Jeep Grand Cherokee Limited
5.7 HEMI/Quadradrive II
Thanks for the replies, if i can get the 4.3l to cruise at 22kts, i would keep the 4.3l in the boat, if not she's gone. The 350 /5.7 would cruise at about 27-28 kts at 3,600rpm.
i can't believe how far mercruiser motors have come since my 1986 -260, all alluminum oil pan w/oil change system, composite timing chain cover, all roller motor, eletrice fuel pump, surpentine belt. it just seems like the updates in the 4.3 itself would almost compete with the 5.7, never mind missing almost 100 cubic inchs.... but,"there is no replacement for displacement" so... ill find out, maybe next week if i have the time.
__________________ B.O.A.T - Break out another thousand
I know several people have swapped out there old 305's rated at 220HP for the newer 4.3L VORTEC's. They have been disapointed in the swap. The lower HP 305 actually pushed the boat better and more efficiently than the higher HP 4.3L could.
IThe lower HP 305 actually pushed the boat better and more efficiently than the higher HP 4.3L could.
That's because the 305 has more torque.
You'll probably be able to cruise at 22 knots, but you'll probably be running the snot out of the engine and you'll lose any fuel efficiency you thought you'd gain.
I am assuming the 4.3 is fuel injected?? Can you obtain some torque curves to get a better understanding of the viability.
In my case, I downsized from a VP 7.4Gi to a 5.7 Gxi. I couldn't be happier with that decision! The 2 engines are rated at 310hp and 320 hp respectively. I lost some torque with the downsize and had to swap out propsets F7 to F5. I lost maybe 4 knots top end and spin 300 rpm faster for a 25 knot cruise speed.
I get at least 15% better fuel economy, shed 200 pounds and gained much better access to the bilge and its pumps and plumbing.
There are alot of 23 footers out there running on a 225 outboard. That 4.3l offers more displacement than the Suzuki 300. I'll wager that as long as you are happy giving up some top end, your boat will run nicely and save on the gas.
__________________
1998 Pro-line 251 Walk-around with VP 5.7 GXi Duo-prop
2006 Pro-line 24 Super Sport w/ 225 Suzuki 4S
Reverse engine swap, take out v8, put in v6! 
