Sometimes the SBC is as fast due to the CG in the boat. My 22 Velocity with a 400 hp BBC was only 72 MPH. With a 6000 RPM junk yard dog 383 cast crank dart headed time bomb with a good pan and dry Stainless marine headers pushed it 80 MPH. It also handled much better and drated less.
Steve

Thanks - the bottom pict was fun- I was passing my buddy in a cole superhawk with a stock bbc.

The price you are quoting are new with all parts, wiring loom cooling, accessories everything and Warranty....

Why doesnt mercury marine sell a 500 HP small block new? ...............


Your solution to reversion isnt - it goes back to the problem of parts.
You cant get longer headers - because no one makes them.

For true headers you get lightning and CMI almost no one even makes SBC boat headers (not sure who else Stellings? )

540304 454 Chevy 36" Overall width 2090.00
540305 454 Chevy S-Bend Style 2390.00
540311 454 Chevy 33" Overall width 2290.00
540330 350 Chevy 32" Overall width 2290.00
540360 460 Ford 39" Overall width 2340.00

Thats lightning Marines price list -all plus plus tails plumbing and connectors CMIS are about the same.

On inventory clearance sales - guess whats always in stock.....

Doesn't seem right....but it is what it is.

UD

Old racing quote, "Horsepower sells cars (boats), torque wins races"

Go BBC, very reliable with lower rpm. Easier to rev match for re-entry.

I would like someone to answer this with a good knowledgeable answer if they can.

Wouldn't having the torque in the higher RPMs be better closer to the rpms you would be running having the most power there to propell the boat the fastest. Wouldn't having the max torque around 5000rpm be better then 3000rpm?

Yes if the boat will plane off.
Steve

Good point, remember Joe Sgro's 28' Manta "Fever", Al Hoffmans 31' Mirage "Armed & Dangerous"? Small Block boats that kicked ass. The 32' Skater "Agitator" was a SBC boat when it raced. All of the above were winners. And yes, all the 27' Magnums, and 28' Cigarettes with the SBC combos worked very well with SBC's, though I rode in a 27' Magnum Sport with twin BBC's for 19 years with TRS drives, and it was and still is a stout combination.

It is hard to argue against a set of BBC for this Scarab application; or order some of the older style SBC (Motown) from Bill Mitchell and have at it. I do like the LSX motors.

I like the formula 292 set up as is. Would love to take a ride in one someday. Very efficient hull IMO.

A SBC at 500 is a no sweat.

Nowadays there 4 inch strokes for them and using a 400 based block with a 4.125 or bigger bore we´re at bigblock territory.
And for a SBC the HPparts are Cheap!
Aluminum heads complete for under 1000 bucks..thats ½ of bigblock prizes... so you end up with twin SBC´s as a winner anyways.

Got any picts or build data?

Curious how you're no sweat setup differs from my no sweat 500HP combo- (which has laid out serious beans for about a decade with little to no maintenance/ the maintenance part being the "no sweat" part to me)

What cam/ manifold carb size brand did you use to make enough manifold vacuum to idle well what exhaust did you settle on ?

How stressed is your valve train? What heads and respective intake exhaust valve sizing - curious.

I too used a 400 block - but side bolted the mains at an increased machining and parts cost but I believe it was worth it.
The mains look sufficiently stout enough to raise the titanic.

All the "little stuff" to make it really work and last pushed my price to equal or greater than a stock BBC.

I find the "devil is in the details" when it comes to SB marine performance.....but thats me..



UD

Uncle dave how much do you think you have in your build and what internals did you go with?
How long ago did you build your engine?
What do you mena side bolted the mains. Did you use a skirted block and run bolts in the side or did you use a 2 bolt block and spay it?
From what I have been learning the strongest blocks are the 2 bolt main blocks spayed because the 2 bolt blocks have more material in the webbing.