Power options for a 233

[John Stepien]

Hi, I have decided that an older Formula 233 is absolutely the most perfect boat for me, and I am looking for one to purchase and restore. I would ultimately like to have at least 400 horsepower in the boat, and I am trying to figure out the best way to achieve that in this boat. Should I buy one that already has twin Merc 165's and try to squeeze more power out of them? Should I put in twin 350s? Can I put in a single big block? I've even thought about adding a bracket to the transom for twin outboards.

Twins are appealing for redundancy, in case I want to venture far from shore. If I am correct in my thinking, twin I/Os will also reduce the draft somewhat because the drives will be a bit higher. This would be a plus, since the chain where I boat 98% of the time is shallow. I'm thinking twins would be more expensive than a single big block, though, and cost is also a factor. The appeal to having the twin outboards is more cockpit seating space, easier repowers, no bellows to worry about, and redundancy. The drawback with twin outboards is that I lose the beautiful teak swim platform.

If anyone has any input that might help me figure these things out, I would greatly appreciate it!

--John

[David]

Don't worry about those twins John. Seriously, twins are twice as much work, twice as much expense, heavier, require more oil, more instrumentation, two throttles, shifters and cables....well, you get the idea. However, they are pretty special and I'd not give mine up. Offshore, twins provide the peace of mind and redundancy that can get you home. It sounds like most of your use will be in shallow water so not sure how relevant that redundancy is. If you want to save money I'd stick with a single big block. Of course, there is nothing like twin V8's through open exhaust, singin' in harmony at 4,000 rpm ; )

[John Stepien]

What do you have in yours, David? Twin 350s? 520 hp sure sounds nice. What's your top speed at WOT? I'm not a thru-hull fan, but might like a captain's call or silent choice. I'm sure twin V8s with through prop exhaust still sound pretty nice! :-)

How much HP can I squeeze out of a 454 while still maintaining reliability and not running the risk of reversion or anything like that? What kind of BB setup would I need to match 520hp?

Thanks!
--John

[David]

I have twin 355 cid with good heads, intakes and exhaust. No dyno specs but estimate about 300 hp each. Top speed approaches 70 under perfect conditions. Mid 60's every day with full fuel load. I would think a 502 could produce 500 hp reliably. Given the fact that you have less weight and less drag I would expect top speed in excess of 70.

[John Stepien]

Wow! That's good to know, and I'm glad I asked. Seems like all the fast boats I've seen have twins, so I just thought that was the way to go for speed. I'll keep a little more open-minded about what I'm looking for.

[Serge Cossette]

I agree with the twin powerplants being X2 everything! But its not twice as fast... Maintenance is also an issue (winterizing for example). Really happy with my 454, even if its only got 330hp. The newer 502 EFI's are really reliable, but pricey tho.

[John Stepien]

Thanks, Serge. Glad to hear another opinion on this. I guess I had originally figured that horsepower is horsepower, but if the speed gains aren't there, I'd rather stick to a single engine. I'll put that 502 on my wish list! :-)

[David Avedesian]

John:

I am with you on all your thoughts listed above. I purchased my 1977 233 in 2000 knowing it had a bad 1995 454ci/300hp big block. It had been laid up with water in the block. It was recommended to me to repower with a remam engine. My counsel is NEVER do that. I made a number of errors in that thought process. I finally decided to repower with a NEW Mercuriser 396ci/375hp EFI, Intercooled engine. Sweeeet. More Hp, More power, More speed, quicker hole shot, 50% better fuel economy, starts with the trun of the key and more smiles per mile than any other set up in my life. What's not to like. Once you get past the $14,000 fully installed one time price, you are in for the time of your life.

I did not want to have through the transom exhaust so I was forced to installed the 375 hp engine. The HO version was 50 hp more but I could not get the exhaust through the Y-Pipe.

With regards to one engine vs. two engines, that is a subjective thought process. I am generally in the school of thought that most engine failures are do to bad gas. Therefore, one engine/two engines you will have a problem no matter. I like the simple approach more than a twin approach.

I love the thought of a Yamaha 4-stoke 350 hp OB. But I am not wild about the look on the back of the boat.

In closing, the hp set up for the boat is great. Top end when first installed before adding all my stuff was 55 mph @ 4,800 rpm burning 32 gph. I have over 450 hours and tons of stuff on board. Top end is 50 mph @ 4,600 rpm burning 30 gph.

I hope the above has been of interest. Good luck and have fun.

David Avedesian
Silver Spring, MD

[GEORGE CATEGE]

I was looking at a 1981 F233 sportsman hull only. Had a 5.7 260 HP in it. I found a 1990 454 with a bravo one (complete set out of another boat) and would like to know first of all if that motor fits where the 5.7 was without alterations or what kind of mods do i have to make in order to fit in it. Also whould like to know what would be the cruising and WOT with that 454 in it. Clean bottom, not much junk in it.
P.S Anything to watch out for on the 1981 F233 besides a good transom?
Thanks.

[Donald]

Do the 233 with twins have a self bailing cockpit? I'm familiar with the 233 fish boats and 24 albes that have the open self bailing cockpit with scuppers. Have there been any boats like this built with twins?