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CHEVYMILL
05-10-2011, 04:58 PM
I have an 89 22c with a Brovo upper and inco 2in shorty I was thinking bout either a mild 454 like 385-400 hp. Or a blown 350 any opinions looking for high 70 low 80 mph

mrfixxall
05-10-2011, 05:27 PM
I have an 89 22c with a Brovo upper and inco 2in shorty I was thinking bout either a mild 454 like 385-400 hp. Or a blown 350 any opinions looking for high 70 low 80 mph

if you have a small block in their now i would leave it a small block,less work for the holes you will have to make in the transom..

check this out! just change the cam and fly!:cool:

http://cgi.ebay.com/ebaymotors/CHEVY-SBC-427-STAGE-5-BOWTIE-CRATE-MOTOR-ENGINE-610HP-_W0QQcmdZViewItemQQhashZitem5199120097QQitemZ35046 0444823QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries

zelatore
05-10-2011, 05:27 PM
For that speed, you'll need well over 400 hp.

For reference, a stock 502 at 415 hp gets you into the low 70s with a standard Bravo 1. Your shorty might be good for a couple extra mph, so let's say 75 mph.

I'd guess you're plan is 100-150 hp short of hitting 80. Perhpas a small block would offer some performance gain from the lower weight, but you'd be working it pretty hard to get the power number you'll need so I'd stay with the big block.

roadtrip se
05-10-2011, 05:43 PM
My boat ran a real world 79-81 with a shorty and a stock 500EFI at 470HP. I would think a hot big block would be the way to make the torque and HP needed to push into the low 80's, and you could stay normally aspirated. Been done many times here. Good luck.

silverghost
05-10-2011, 06:02 PM
Chevymill:
What engine do you have in the 22 now ?
I too would stick it a normaly asperated Big-Bock Chevy.
The Big Blocks would give you much more torque than a small block.
You need torque, as well as more horsepower, to push that Donzi 22 into the 80 ranges.
The extra weight of a Big-Block is a good trade-off for the extra torque & power.

CHEVYMILL
05-10-2011, 06:09 PM
I bought it with no motor but it had a mild 454

mrfixxall
05-10-2011, 06:14 PM
all you guys are under estimating the true power that a blown small block can make let alone the weight savings compared to a big block..you can build a healthy blown small block to what or for the same price as a big block..for example geoo's x18,440 cubes and a procharger.in the neighborhood of 1000 hp..:yes:

Ghost
05-10-2011, 06:53 PM
Curious how much maintenance cost (rebuild interval, etc) difference there is between what Fixx is describing (a more pumped-up smallblock) versus a less-tweaked big block.

And contemplating weight, how light of a motor is optimal for a 22C? I imagine at some point it might even be TOO light, such that the COG is too far forward.

What I was thinking was that while I don't doubt Fixx is right about what can be done at the more hi-po end of the spectrum, to reach low 80s, there might be a better cost/maintenance interval compromise by using a lightened big block. For instance, with only Stainless Marine exhaust, won't you save about 90ish lbs of the 210 lb delta betwen small and big block Mercs? Also, I don't know what a blower weighs, but that would also diminish the delta between the blown SB and a NA big block. (Of course, you could put lightweight exhaust on the SB too, so that part may be moot.)

Just a thought. I don't pretend to know the answers, just curious.

silverghost
05-10-2011, 06:54 PM
Fixx:
All you said about small blocks is in fact true.
But at what cost both in dollars long term reliabiity to get you there ?
How long will that blown & worked stroker small block last ; compared to that much lower build price Big block ?
The Big Block Platform is built like a bulet-proof tank with bigger bearings, crank rods. After all it was once the Hi Performance Pass. auto & truck platform.
In a Donzi 16 & 18 I'll take the stroked & worked Small Block,
In the 22 the Big Block.

That's just my point & my opinion.

roadtrip se
05-10-2011, 08:07 PM
I ran the crap out of my HP500EFI for ten years, a decade, before I started even thinking about a refresh. Even now, I could have just done some freshening work to the top and kept on going, but chose to go a slightly different direction, as in more normally aspirated BB power. And it ran 80 pretty much on demand with very little aggravation. That is real world.

Planetwarmer
05-10-2011, 09:59 PM
BB= Bigger Bragging Rights!:)

The Hedgehog
05-10-2011, 11:03 PM
BBC all the way. I love blown engines but if you want those numbers in a 22 then that is the way to go. 18's are a different story...SBC for those. 22's have the space for a nice easy BBC

Rumblefish
05-11-2011, 07:14 AM
Im a big block guy.. but....


A supercharged small block would be able to keep a torque curve to pull a 26p or so in to higher rpms if electronic rev limiting would be changed .

Where as a 500hp big block running 5100 rpm would be propped at 28p or higher to achieve the same goal.

As far as weight... its like adding a passenger or taking one out of the back seat.

In the end. they are both good ways , but Big block normally aspirated power is my vote

( as roadtrip said) 80 on demand..

MOP
05-11-2011, 09:38 AM
There is a phrase "Nothing like Cubic Inches" no one can deny that a built big block will out perform a built Small block. But remember one thing all Donzi's were "initially" designed for small blocks, having driven both varieties the small block handling and wake jumping control is much better. My pick would be pro charged 383 with a shortie, setup right it would go where you want to go and still retain the boats best handling characteristics.

Phil

Carl C
05-11-2011, 10:10 AM
Another vote for BBC, especially since that is what the boat is already set up for. You will need over 500 HP to reach your goal. That 427 small block with a 300 hp nitrous kit (spec sheet says it can handle it) would be a lot of fun in a street car though....:convertib:

Sweet little 16
05-11-2011, 10:25 AM
But remember one thing all Donzi's were "initially" designed for small blocks, .........
Phil
That is not correct, right from the start the early donzi were fitted with big blocks , in any one that could fit ( not the 16)one so the hornet and sportsman got big block v drive power even the early 18s . Due to cost and the increasing power available thru the stern drive most ended up with small blocks and volvos but to say they were designed for that ain't so.

Even when the 22 first came on the scene as the criterion and f 22 they were 454 trs boats weren't they?? Please let's not confuse a marketing strategy early in the OMC Genth era to make the 22 lighter and go 60 with small block power to increase their bottom line as a design initiative.


I mean there are a ton of sayings
go big or stay home
size matters
there's no replacement for displacement
so there's got to be something to it. there are alot of choices out now getting 400 hp out of a small block is common place . I guess one needs to decide what's right for them. durability,economy,ego :p ease of maint., and what type of performance they are looking at.

mrfixxall
05-11-2011, 11:16 AM
ok all the desk jockeys, if you had a choice of a 496'' BB or a 496'' small block with the same bore and stroke which one would you go with??

maddad
05-11-2011, 11:39 AM
ok all the desk jockeys, if you had a choice of a 496'' BB or a 496'' small block with the same bore and stroke which one would you go with??
If all I had to do was pick, it would be lighter smallblock. If I had to pay, I'd go for the big block without all the expensive/custom smallblock parts.
Now a 415 or 420 sbc would be cheap enough where I'd rather have it than the bigblock. Even with the 75 inch handicap.

Fishermanjm
05-11-2011, 11:57 AM
i know i'm totally green when it comes to these boats,,, but from the one time i was out in mine last year the boat was a srceamer and was a lot of fun with the 6.2 that she came with,,, one day i might change my mind on that, its a go fast boat thats sounds awsome, i love my Donzi

MOP
05-11-2011, 08:03 PM
Jim has mentioned a 22 with a 6.2 and a shortie down his way that ran real well, and like I said the handling is much better. If you get chance to drive a big block you will be surprised at the difference. Phil

roadtrip se
05-12-2011, 11:36 AM
Jim has mentioned a 22 with a 6.2 and a shortie down his way that ran real well, and like I said the handling is much better. If you get chance to drive a big block you will be surprised at the difference. Phil

Okay, I will bite Phil, but I do have a couple of questions:

1) What exactly do you mean by the "handling is much better"?

2) Per the first post at the start of this thread, where we were seeking high-70's or low 80's, how many small block 22's have you seen accomplish this?

I will give you my answers to these questions:

1) After just juicing, and I mean really JUICING, the HP in my C22 BB, I would never attempt to run the boat at 80+ if the handling wasn't predictable and safe. My boat has awesome balance, requires zero tab input, and runs very hard with no handling compensation, whatsoever.

2) I can count at least a dozen C22 boats that run at least 80 and some, well over that, with BB power. Not saying that it can't be done, because it can, but I can't count one C22 with a small block doing it now.

Why mess with a proven formula? If you are expressing an opinion, I respect that, but real world results show the BB pathway will get you there, and with the added bonus that there are several folks in the community with experience doing it that can help along the way.

MOP
05-12-2011, 10:21 PM
Todd it is nothing more than two different mind sets, No argument if you want to get into the high 70's and above a BB is the way to go. And yes I only know of one SB 22 that topped 75 it was a non blower 383, there may be others who knows. I like the lighter feel the feather light landings nicer feel at high cruise speeds, like the many I enjoy watching you high HP boys run. IMO at the speeds some run things happen way to fast, Ken got thrown out of his 22 at under 70 when he did not notice a small wake.

younger
05-12-2011, 11:51 PM
To build 550, 600hp today in either sbc or bbc is very easy to do. To have a strong foundation to build the motor is when it changes things. The bb can be done on factory castings and be very strong. To build a sb today the factory casting just don't do it to be reliable at these levels. Once you make the call to dart, world etc. for the block and supporting parts to make the sb mean, it adds up fast. As for power the bb can spin slower to provide a more usable curve. That is the reality of it. That is why boat builders have used the bb for so long. It is cheap, reliable, and makes power. Just imagine if merc built a large cube sbc that made big torque and hp, was fuel injected, all aluminum to stay light, and was cost effective. Wow! Move over rat here comes the mouse!

osur866
05-13-2011, 01:26 AM
Well, in a 22 I'd go with a BB for most of the reasons stated, as far as higher HP SB's go, I just had one put together and we will see how reliable it will be. It is right at 600 HP, I'd think a 600 HP SB Vs. A 600 HP BB in a 22 the BB will last longer and labor less. An 18 or 16 I'd think the weight savings of the SB if power was equal would be a much better handling drivable classic. As far as weight of the blower, yes they may weigh a lil more than a OEM mpi but swap the cast iron heads for a nice set of aluminum and I'd say you have actually saved weight over stock. Swapping just exhaust on a late model SB to stainless marine will save you exactly 83 lbs. I know for a fact my boat runs flatter since doing my engine upgrades, took off OEM mpi added Whipple took off cast heads put aluminum on.

MOP
05-13-2011, 07:05 AM
I am tainted I love SB's, I built a fairly radical/very mild cammed 383 based on an 010 four bolt block. It is stuffed with a full Lunati Pro Mod kit with Dart heads, with a cam change it could make some serious HP Lunati rep said it can run six digits all day long not my goal! I wanted a people hauler for both work and play, I wanted reasonable economy having to make long runs with customers. I am running the power the power through a Bravo Diesel X, I don't like things that break this setup will be around longer than most. On a good day it will top 65.5 and at 3300 it cruises at 43 on GPS getting 4mpg, I know this type of setup does not appeal to the fast set but is perfect for many and be around for the long haul. Phil

Donzi_Dude
05-13-2011, 10:56 AM
I am tainted I love SB's.

Phil

do you mean you love SBC's?

im a small block guy too. i seem to do good with the fords, olds.

in a marine appliction BB wins/wins. in small boats with very high HP applications a small block has its place but its not a mild HP pleasureboat application.

younger
05-13-2011, 11:00 AM
I as well am a sb guy. Have build many sb for boats over the years. The latest is the 415 that is in the bh 16. These motors are plain awsome!! It weights just shy of 200lbs less than the 4.3 that came out of the 16. As for the sb and fuel price no contest. Even though I staited bb for build cost. For me, when I build a 22 it will be large cube sb bravo xr imco -2 lower. Should do the trick, and when the hatch is open its a fast 350.

mrfixxall
05-13-2011, 12:49 PM
I as well am a sb guy. Have build many sb for boats over the years. The latest is the 415 that is in the bh 16. These motors are plain awsome!! It weights just shy of 200lbs less than the 4.3 that came out of the 16. As for the sb and fuel price no contest. Even though I staited bb for build cost. For me, when I build a 22 it will be large cube sb bravo xr imco -2 lower. Should do the trick, and when the hatch is open its a fast 350.


the future..

http://www.mastmotorsports.com/2010/product-view.php?cat=Marine&id=396

Donzi_Dude
05-13-2011, 01:18 PM
the future..

http://www.mastmotorsports.com/2010/product-view.php?cat=Marine&id=396


looks impressive. what drive would hold up to the rpm range/HP?

Carl C
05-13-2011, 02:08 PM
the future..

http://www.mastmotorsports.com/2010/product-view.php?cat=Marine&id=396

Has anybody bought one yet? Their site shows that they are mainly about car engines. Running an engine up to red-line for a few seconds at a time and holding one there for quite a bit longer are two different things. I'll be a believer when someone actually builds an 80+ mph small block 22C that is reliable and durable.

mrfixxall
05-13-2011, 02:32 PM
Has anybody bought one yet? Their site shows that they are mainly about car engines. Running an engine up to red-line for a few seconds at a time and holding one there for quite a bit longer are two different things. I'll be a believer when someone actually builds an 80+ mph small block 22C that is reliable and durable.


maybe this will answer your ?

http://www.youtube.com/watch?v=7YtkD8CXnW8

also here is a ls7 skater,,seems to push the boat well over 100 mph

http://www.youtube.com/watch?v=hhPuadVmK_k&feature=related

pipnit
05-13-2011, 03:55 PM
SBC, especially if you already have one.
I'm hopefully starting my new 383, .040 over tomorrow with a little luck, otherwise it'll be next week.

my SBC will be over 500hp on 87 octane. Should move my 18 footer pretty well!

osur866
05-13-2011, 08:58 PM
SBC, especially if you already have one.
I'm hopefully starting my new 383, .040 over tomorrow with a little luck, otherwise it'll be next week.
my SBC will be over 500hp on 87 octane. Should move my 18 footer pretty well!
Yes 500hp will move an 18 well :)