454 vs 350

[CHEVYMILL]

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]

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!

http://cgi.ebay.com/ebaymotors/CHEVY...Q5fAccessories

[zelatore]

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]

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]

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]

I bought it with no motor but it had a mild 454

[mrfixxall]

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..

[Ghost]

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]

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]

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]

BB= Bigger Bragging Rights!

[The Hedgehog]

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]

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]

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]

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....