And I thought Bill Mitchell's 454 small block was the limit ...

[Ken]

Until I saw this: :eek

:J A 472 cubic inch small block Chevy with 635 horsepower!! ​

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http://www.shafiroff.com/​

 

[Stallion]

How can that still be considered a small block? What makes a small block a small block and a big block a big block?

 

[vetteboy86]

That is what i need

I think when they say small block vs. big block it is the actual block dimensions. A small block can have any size cubic inches, that just denotes the combustion chamber size. However the actual block size is different, big block bieng bigger offcourse. This was in issue in the early 70's when the big blocks werent making much more hp then the small blocks. They did way more, so it was a toss up which was better. I hope I am accurate in my answer.

Craig

 

[JohnZ]

Small-blocks have 4.4" center-to-center bore spacing, big-blocks have 4.84" bore spacing. Not one basic engine part is interchangeable between them.

 

[Stallion]

So that 472 SBC probably doesn't have too much material between each cylinder. Unless it has a huge stroke and not as much bore as we would expect.

 

[vetteboy86]

So would that mean that they are larger, because I thought for sure they weighed more. Wouldn't they have to be bigger. It is hard to tell in my case because if I looked at the 455 in the trans am it looks alot bigger then the 350 in the vette. This could be due to the fact that the Trans am doesn't have anything else under the hood except the engine, while the vette on the other hand has a whole bunch of stuff under the hood.


Craig

 

[SPANISHVETTS]

So that 472 SBC probably doesn't have too much material between each cylinder. Unless it has a huge stroke and not as much bore as we would expect.

I would think that any SBC over 400 cubes has simonized cylinders, i.e. the Rocket 400 block that we all

over. The stroke is limited by the deck height so at some point we reach the limit of increasing bore and stroke. This animal looks like it is pushing the limit.

In Spain the 3 Kings (wise men) bring presents on the 6th. Maybe they will bring me one.

 

[Stallion]

So when people say that a big block puts out more torque than a small block, it really has nothing to do whether it's a big or small block...? For instance, this 472 is a small block, but has more displacement, so it would probably put out more torque than a 454 big block. No?

 

[Ken]

Spanish, they are siamesed bores, but you already knew that. Here are the rest of the specs:

• Dart Tall Deck Iron Eagle 4Bolt HP Block with Raised Cam & Splayed Steel Billet Caps
• Callies 4340 4.250 Stroke Internally Balanced Crank
• Eagle 4340 H-Beam 6.125 Steel Rods w/ARP Bolts
• JE 10.5-1 Custom Forged Aluminum Pistons
• Air Flow Research CNC Ported 227 Aluminum Heads
• Dart CNC Ported Intake Manifold
• Ultra Street Big Dawg Polished Aluminum Valve Covers
• Offset 1.6 Ratio Aluminum Roller Rockers
• Moroso Street/Strip Oil Pan, Oil Pump & Pick Up
• Chrome Timing Cover w/ Tavia Pointer
• HP Harmonic Balancer
• Internally Balanced
• Professionally Blueprinted and Assembled
• Every Engine Dyno Tested w/Dyno Sheet Provided

Plus, there are many more options available.

 

[Tom Bryant]

I'm speachless....almost. I wonder what the absolute limit is with 4.4 center to center bore spacing?

 

[JohnZ]

So when people say that a big block puts out more torque than a small block, it really has nothing to do whether it's a big or small block...? For instance, this 472 is a small block, but has more displacement, so it would probably put out more torque than a 454 big block. No?

Correct - displacement is displacement, regardless of the physical size and weight of the block; assuming the same bore and stroke dimensions, compression and tuning elements, there wouldn't be any difference.

The older Pontiacs took a different tack - they all used the same size block casting, from the 326 to the 455; just changed bore sizes and crank stroke combinations in the same physical hunk of iron.

 

[Ken]

I sure do miss the days when Ponchos ran hard at the drag strip.

 

[67HEAVEN]

Correct - displacement is displacement, regardless of the physical size and weight of the block; assuming the same bore and stroke dimensions, compression and tuning elements, there wouldn't be any difference.

I'll still take that beautiful semi-Hemi BBC head design.

 

[Ken]

:cool

 

[Jack]

Seems at 472 it's already 0.080" over ... one hiccup and it might need new block & pistons ... or simply another $12K. Wonder if they're using new first quality dart blocks or ?
JACK:gap

 

[SPANISHVETTS]

Have a look at this

 

[SoLow]

Big Block in a C4

Ken, I have been thinking about putting a 427 Big block into my 87....What do you think? :confused

 

[DRTH VTR]

I hope that somebody who knows more about this than I do will correct any errors here. I thought that, in general, a longer stroke (with the same displacement) will increase torque, but limit the RPM's at which the engine can operate, while a shorter stroke can decrease torque, but raise the RPM limit. Any truth to this?

 

[Ken]

Wonder if they're using new first quality dart blocks or ?

Here are the rest of the specs:

• Dart Tall Deck Iron Eagle 4Bolt HP Block with Raised Cam & Splayed Steel Billet Caps
• Callies 4340 4.250 Stroke Internally Balanced Crank
• Eagle 4340 H-Beam 6.125 Steel Rods w/ARP Bolts
• JE 10.5-1 Custom Forged Aluminum Pistons
• Air Flow Research CNC Ported 227 Aluminum Heads
• Dart CNC Ported Intake Manifold
• Ultra Street Big Dawg Polished Aluminum Valve Covers
• Offset 1.6 Ratio Aluminum Roller Rockers
• Moroso Street/Strip Oil Pan, Oil Pump & Pick Up
• Chrome Timing Cover w/ Tavia Pointer
• HP Harmonic Balancer
• Internally Balanced
• Professionally Blueprinted and Assembled
• Every Engine Dyno Tested w/Dyno Sheet Provided

Plus, there are many more options available.

 

[WhalePirot]

I hope that somebody who knows more about this than I do will correct any errors here. I thought that, in general, a longer stroke (with the same displacement) will increase torque, but limit the RPM's at which the engine can operate, while a shorter stroke can decrease torque, but raise the RPM limit. Any truth to this?

I won't claim to know more, but that's largely how I understand it. The crank does this direction change thing for the rods and pistons and all of it must be strong and/or light enough to make higher revs with that longer throw of the crankshaft. The longer stroke (throw) is the simple physics a longer lever, delivering more power (torque). The space available in a SBC physically limits how long that stroke can be. We know the 350 has to be machined for the 'stroker kit' that makes them 383s.

One thing I like about my 406 is the BBC-like stroke, which yields awesome pull, yet revs nicely. Would I like the 9000+ revs of a 302? Sure, but for street use, 6300 does nicely.

Dang it, Ken! I used to think I had enough power!