Foggy Torquay 15th April ,Silverline !

[Matt]

Err, yeh! You gone blind from too much
http://boatmad.com/forum/showpost.ph...1&postcount=31

I know the GM spec of a 496, but the spec you posted for the bulldog gave a capacity of 496, hence why I said it aint a 496.

[Matt]

Yeh, I believe that's the factory listed max bore.

Originally Posted by Jon Fuller

And, is the 4.56 the limit on the GM wall thickness? I'm assuming the Bulldog tall deck motor is the GM bow-tie jobbie, mebbe it could go more. the 4.625 bore gives a piddly 588ci!

[Matt]

Ere, I take exception to that, nothing I posted on this thread is a guess, stop trying to score points by being smart.

Originally Posted by Jon Fuller

(not a educated guess, the actual spec, as a GM 496 is not 4.375 S, it's 4.00)

[Jon Fuller]

Originally Posted by Matt

Ere, I take exception to that, nothing I posted on this thread is a guess, stop trying to score points by being smart.

I aint smart, that's the only thing I'm certain of!

And I don't need points.

[motorvator]

Jon,

I think Matt is losing himself with charts!

Bulldog was based around the 454ci 7.4l 4.25 x 4.00 block with 542ci 8.9l from 4.40 x 4.375

old hp 525 sc etc were standard 454 block size

HP500 was a 502ci 8.2l block 4.47 x 4.00

From that came the HP500efi, HP525efi, HP575sci, HP600sci, HP700sci all at 502 dimensions.

HP 850sci, HP1025sci, HP1075sci HP1200sci are 557 ci 9.1l 4.5 x 4.375

There was an HP800sc listed at 572ci and a 575 / 540ci which I haven't a clue about.

I don't know if the tall deck block was bow tied or siamesed but I would imagine so. I would imagine some of the other blocks were too. Whether they used tall deck blocks or shorter rods I haven't a clue either.

Only reference I can find to your 482 is the old 460trs? which being before the birth of 502 blocks would have been based around the 454 so 4.25 x 4.25 as you say.

All other sizes I think were used by Sterling et al for there own builds.

496ho is 8.1l 4.25 x 4.38

Now I believe I'm right in saying the 454s were gen 3 through 5 and the 502s gen 5 through 6 which gave the differences of 2 or 4 bolt mains, one part seals, rerouted cooling, roller lifters and square / oblong ports being the major differences along with doing away with a petrol pump drive.

I think

[Jon Fuller]

I'm pretty certain the Bulldog (detuned MCM575-540) is a tall deck motor. (which the 330, 365, 370, etc, etc weren't)

The 482 is the 1982 class 1 & II EFI motor that came out of Warlord.

[Jon Fuller]

Originally Posted by motorvator

496ho is 8.1l 4.25 x 4.38

Is that deffo?

found this:

"A L18 496 8.1L 8100 vortec is a truck motor! Its not a 454 redone. Its has a odd bore 4.440 and 4.00 stroke. It is a tall deck motor and is like 50-75lbs heaver than a stock 454."

But having never looked up the spec of a merc 496 i don't know

EDIT>

just looked at merc's website, and it appears that first line (from a car site) is wrong. http://www.mercurymarine.com/engines...96ho_specs.php

[Matt]

Err, no, I think all the specs I quoted are accurate - I never said they were standard merc sizes did I!

I think you lot are losing yourself on the merc catalogue.

Wozza posted a bulldog bore & stroke that equated to 496cu, rather than the 540 cu. He then quoted a bore and spec for the 572 which is not the same 572 that GM performance parts do - although sterling, or even merc etc may offer others, I dunno.

The bulldog wasn't based on a 454 other than it's a "big block" - it's a bowtie talldeck block - unless you're referring to it's generation, in which case I think it is a MkIV block - but not sure.

Originally Posted by motorvator

Jon,

I think Matt is losing himself with charts!

Bulldog was based around the 454ci 7.4l 4.25 x 4.00 block with 542ci 8.9l from 4.40 x 4.375

old hp 525 sc etc were standard 454 block size

........

[motorvator]

Originally Posted by Jon Fuller

I'm pretty certain the Bulldog (detuned MCM575-540) is a tall deck motor. (which the 330, 365, 370, etc, etc weren't)

The 482 is the 1982 class 1 & II EFI motor that came out of Warlord.

Wouldn't be at all surprised Jon. Never understood why they didn't make more use of tall decks given stroke being the winner in torque stakes.

460trs manufactured 83 to 85 so makes sense too. She was speedmaster drive though?

[Jon Fuller]

I wonder if the 4.38" stroke they quote for the 496 is really the 4.375? seems strange that they'd make summat with a 5 thou differnt stroke. mind you, having never looked into the 8.1 motah, I always assumed it to be acompletely new block, and it looks like it might not be.

[Matt]

Very limited parts combination might have been a factor (purely speculation though) - I think the modern big capacity motors now are still often standard deck, but with raised height pins in the pistons so that the rod angle isn't excessive for the larger stroke.

Originally Posted by motorvator

Wouldn't be at all surprised Jon. Never understood why they didn't make more use of tall decks given stroke being the winner in torque stakes.

460trs manufactured 83 to 85 so makes sense too. She was speedmaster drive though?

[Matt]

Is it right the head castings are different - ie the exhaust for the 496 wouldn't fit a 502?

Originally Posted by Jon Fuller

I wonder if the 4.38" stroke they quote for the 496 is really the 4.375? seems strange that they'd make summat with a 5 thou differnt stroke. mind you, having never looked into the 8.1 motah, I always assumed it to be acompletely new block, and it looks like it might not be.

[Jon Fuller]

Originally Posted by motorvator

460trs manufactured 83 to 85 so makes sense too. She was speedmaster drive though?

Well, remember that a class1 motor of the time was 600+ hp (I think the spec claimed 650), and yes, it was on a #3 speedmaster. a pure race engine.

[motorvator]

Originally Posted by Matt

Err, no, I think all the specs I quoted are accurate - I never said they were standard merc sizes did I!

I think you lot are losing yourself on the merc catalogue.

Wozza posted a bulldog bore & stroke that equated to 496cu, rather than the 540 cu. He then quoted a bore and spec for the 572 which is not the same 572 that GM performance parts do - although sterling, or even merc etc may offer others, I dunno.

The bulldog wasn't based on a 454 other than it's a "big block" - it's a bowtie talldeck block - unless you're referring to it's generation, in which case I think it is a MkIV block - but not sure.

Correct Matt, Bulldog is GenIV so clearly from the 454 stable as 502s were GenV onwards.

I say the 454 stable as cylinder wall thicknesses differed between the 454 and 502. Talldecks are just taller versions of the same block and not all bowties are talldecks.


In my honest opinion which could be total bollox

[Jon Fuller]

Originally Posted by Matt

Is it right the head castings are different - ie the exhaust for the 496 wouldn't fit a 502?

I always thought so, but TD reckons the exhaust manifold gaskets he ordered for Andy's 496 to fit the CMI's was a standard large port BBC part number from merc.

BTW, andy is selling his boat, you should try and buy the headers if they fit!

[Jon Fuller]

Originally Posted by motorvator

I say the 454 stable as cylinder wall thicknesses differed between the 454 and 502. Talldecks are just taller versions of the same block and not all bowties are talldecks.

My memory of getting stuff for dicks HP465's, were that they were bowtie siamesed, 502's (I thought all 502's were siamesed, so to accomodate the extra bore).

They deffo weren't tall decks and were 4.00 x 4.47.

[motorvator]

Originally Posted by Matt

Is it right the head castings are different - ie the exhaust for the 496 wouldn't fit a 502?

I was with Jon in that I thought they were a totally new casting too. Never looked into 496 myself either.

[motorvator]

Originally Posted by Jon Fuller

my memory of getting stuff for dicks HP465's, were that they were bowtie siamesed, 502's (I thought all 502's were siamesed, so to accomodate the extra bore)

They deffo weren't tall decks and were 4.00 x 4.47

edackery

[motorvator]

465 (GEN. V) GM 502 V-8 1992-1994
465 GM 502 V-8 1990-1992


As i'm not allowed to edit due to black helicopter action

[Tony Davis]

Originally Posted by BluFin

MMMH..........



maybe a winning invite to the D2S lauch party

2nd prize is 4 tickets to the launch party!