Start with a sorta special small block. Add the marine stuff. Add stronger parts. Invent stuff to fill in the gaps.

Get around 500 plus ft. lbs. of torque at 3,000 rpm. That is is big block number.

What defines a special small block?

Super Charged ?

Nope.

Chevy all aluminum small block.

It sounds good. But, if I were buying, I would have to 'feel' it first.

I would like to see the torque numbers from 0 to 5,000. What is 'special' about this base small block you're starting with?

And, what kind of stuff are you 'inventing' to fill the gaps?

Oops, sorry.

Think Corvette type. This one is 434 cubes.

I am not inveenting anything. The selling engine builder did.

The scale of the torque ban over all rpms has not been disclosed yet.

Peak Hp is 550 Hp at 5,500 rpms. Peak torque is 565 ft. lbs. at 4,400 rpm.

Just for D-Rod, the engine builder uses electronic variable valve timing in this engine. Adjusts via load and rpm. Said to broader the torque ban.

Sorry, I didn't mean you seabuddy. I meant that in a more generic sense. "You", as in whoever the builder is. What are they inventing to provide more torque from a small block?

434 C.I.D. is quite large for a "small" block. Do you heve the bore and stroke dimensions?

Special engine crank, so, no, I do not. Think about like the numbers from that 7 litre Corvette engine.

Note the enhansed closed cooling system that allows aluminum to last in salt water. Far more of a system than most closed cooling systems that are used within the marine engine industry. Custom created.

Also note, the 4 tube header system. Custom, also. This engine comes with these headers.

Other special parts in addition to the crank...pistons, rods, intake and exhaust valves, valve springs, and that camshaft set-up.

Cost ???

There may be more, I was taking notes as fast as I could. Sorry if I missed anything.

Oh, pricing. Figure like about five to six times what you could put together a regular 280-300 Hp type small block for if one shopped for 280-300 Hp type parts.

Drive parts are priced and sold separate. Or they will sell just the engine.

Not for LSx based motors. I've heard about one knocking on the door of 500 cubic inches.

Sold by regular marine engine builders for boat use?

No. Race and street motors though.

On land, for the street or the strip?

In small production runs or as a one off?

Cost = 5 - 6 times the cost of...

Quick, ball park answer. Put this engine into your boat, hooking it up to your existing Duo-Prop drive, and using the provided by the engine builder 4 tube headers about $27,000 to $31,000.

So if you want the fastest 206 boat in the East...

27-31k extra over the standard 5.7?

Sounds a little too costly to be the standard big block replacement.
Probably cheaper to build an SC engine.

I can't help but keep thinking you can make a 434ci 400 based SBC, for a lot less.

I wouldn't use a 400 sbc block for marine use. Thier larger bore is nice, but the cylinder walls are siamesed, no water jacket, just some small steam holes. These blocks are (maybe just were) notorious for getting hot on the sides if the engines were built up too much, or run at higher rpms for extended periods.

For the next generation of marine engines, I say scrap the old SBC, use the new 6.0 platform. They are getting good power from that engine, and it is more efficient. Put a supercharger on the 6.0 and you'll have a fire breather.

For a Gen 1 434SBC, I probably wouldn't use a GM block anyway -- I'd go aftermarket. Run a Dart Little M probably.

Do they have a 4.125 bore? I don't know much about the little Dart blocks.

As for seabuddy's engine posting, i would like to learn more about thier offering.