RazorsEdge

Has anyone here rebuilt their engine or build a shortblock from scratch? How difficult is it to do? I have swapped out the top half of car engines before but have never tried to build/rebuild a shortblock. If I purchase the correct rotating components components already balanced (I would check them of course) and purchased a merlin III block (race prepped)(4.500'' Bore 9.800'' Deck Height) 9.0:1 compression, complete merlin Heads and intake, how difficult would it be?

I would think that it would be better than an assembly line motor, much more care being taken when building. I do have the book Big-Block Chevy Marine Performance by Dennis Moore and have read it several times.

I am looking for very high grade components but not looking to put out a huge amount of Horsepower. I would like to build a BBC putting out around 500 HP turning in the neighborhood of 5,500 RPM's.

What additional machine work would be needed before assembly? Any recommendations on additional reading?

FASTERDAMITT

Basically what I do is take everything to my machinist for his prep and balancing ect. I will conference with him on assembly for any new tech I'm not up on. Be sure to call the manufacturer tech lines for input too. Just be sure of everything and double check if you don't remember if you torqued something.
I built almost every engine I've had in the last twenty years but the engine in my Superboat. I probably could have but to get 800hp on natually asperated engine I figured best if i had someone with experience and a one year warranty as well. More later.

Pat McPherson

Hey Razor,
What engine do you have in your boat now?
If it's a 454Mag, that can be rebuilt to make 500HP @ 5600rpm no problem.
There is no need to buy an expensive aftermarket block or heads unless you want to make 600HP+.

FASTERDAMITT

I agree. My American Offshore cat was a 454Mag with a good cam and heads. Bolted on a Procharger and I was over 700hp and doin 100+.

Stormrider

Would the great ci give more torque? so you could break more bravos?
Pat, could one of the volvos you get be built up to 500hp easily?
... actually a raylar kit on one of those would be nice.
... buy the volvo and just do the upgrade w/ the raylar.

Pat McPherson

Yes, Torque is easier to build with more cubes.
Yes, the Volvo 375HP or 420HP 496 cube can be built up with a Raylar kit. But now the $$ are going to flow from your wallet...

If 500HP is the goal, a 454mag is a good base for modification...

Hey Storm,
What did that modified 454mag JC Perf. built for you dyno at?
Over 560HP @ 5800 if I remember correctly...

Stormrider

Yup... 552 @ 5800, 558 @ 6000 and torque at 552 @ 4800.
If all you want is 500hp, no need to go more than 454.
I guess its all about your budget.
I just thought since Razor has experience w/ the top end, he could do the Raylar package w/ confidence.

Stormrider

Pat, btw... spoke to the new owner of my boat today.
He loves it. and is thinking of putting a 1-2" shortie on it.
I'm glad its in caring hands.

RazorsEdge

The engine is 10 years old and I would like to race (P6 if it lasts for the 2007 season and P5 if it doesn't). I was calculating the costs of a Merlin III short block race prepped, World balanced rotating assembly, all the odds and ends, plus the merlin single plane manifold. I was talking to World performance, the block needs no additional machining after it is race prepped. Parts for what I am looking to do is not much more than a replacement "rebuilt" short block in the 502 Mag variety.

I would like similar internal specs to the Merc 500 Bulldog without the price tag. I would like to build as close to a bullit proof race engine as possible. Looking for the ability to run 70mph all day long (almost as if it was cruising speed) without breaking engine parts.

Is this a lost cause? My current engine is a Gev V Carb (350 at prop)
Full Hydraulic steering will be hooked up within the next couple of weeks.
New 3 button Livorsi Throttles will be hooked up this week. My Trim indicators will be added somewhere in the mix. Have not made the measurements for the indicators yet.

I do not really care about top speed but being able to hold the throttle between 60 and 70 mph with reliability is.

Thanks,

RazorsEdge

I am still looking to do the build, (cubes vs rpm debate). I would love to see the spec's on Stormriders motor. What his top speed at RPM and what his cruise speed is/was?

Would a motor like that be able to carry my 24' Superboat at 70 for extended period of time with reliability?