Small Block, Big Block what is the differnece?
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Joined: Dec 2005
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From: Titusville Florida
Small Block, Big Block what is the differnece?
What is the difference between a small and big black engine? The obvious answer is size, displacement but I read an article some time ago that went into measurement between the middle of cylinder bores and maximum displacement capability and some other data.
The LS engines have confused the issue and if you try looking elsewhere on line it is a zoo of answers.
400 ci small block, 396 cu big block, 427 small block and on and on.
So I came to the experts.
So does anyone have the definitive answer?
The LS engines have confused the issue and if you try looking elsewhere on line it is a zoo of answers.
400 ci small block, 396 cu big block, 427 small block and on and on.
So I came to the experts.
So does anyone have the definitive answer?
Le Mans Master
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From: Memphis Tennessee
Using the minimum number of words, it all about bore-centers of the cylinders and the related geometry thereafter.
Stroke too can determine displacement, but torque and terminal revs are also relative to bore vs. stroke. Large(er) displacement / short(er) stroke engines rely on bore so the dimensions of the small-block limits many factors when you get into larger cubic inches
Stroke too can determine displacement, but torque and terminal revs are also relative to bore vs. stroke. Large(er) displacement / short(er) stroke engines rely on bore so the dimensions of the small-block limits many factors when you get into larger cubic inches
Last edited by ALLEGRO; Jan 7, 2017 at 09:29 PM.
1/4 mile/AutoX
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From: Buffalo Texas
the term originated in the 60's by the physical size of the engine block. 283,327,350, small block. 396, 427,454 big blocks there was also a 400 small block. Pontiac, Olds. was the same, size of the block !! I don't think it pertains to the LS series cause they are the same size block.
1/4 mile/AutoX
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From: Buffalo Texas
Burning Brakes
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Small Block and Big Block were descriptions assigned mainly to the "Big Three"; Chevy, Ford and Chrysler. IIRC Chevrolet initiated the monikers in the late 60s.
Basically it came down to small block = small bore, short stroke. Big block = large bore, long stroke.
LS blocks are just that LS blocks or LS series.
Basically it came down to small block = small bore, short stroke. Big block = large bore, long stroke.
LS blocks are just that LS blocks or LS series.
1/4 mile/AutoX
Joined: Jun 2014
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From: Buffalo Texas
Small Block and Big Block were descriptions assigned mainly to the "Big Three"; Chevy, Ford and Chrysler. IIRC Chevrolet initiated the monikers in the late 60s.
Basically it came down to small block = small bore, short stroke. Big block = large bore, long stroke.
LS blocks are just that LS blocks or LS series.
Basically it came down to small block = small bore, short stroke. Big block = large bore, long stroke.
LS blocks are just that LS blocks or LS series.
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Drifting
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From: Danelaw
There was also a 366 cu in Big Block, but they only put those in Commercial trucks.
The LS motors are definitely small blocks.
1/4 mile/AutoX
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From: Buffalo Texas
that is a LS engine !!
The LS based GM small-block engine is the primary V-8 used in General Motors' line of rear-wheel-drive cars and trucks. Introduced in January 1995, it is a "clean sheet" design with only rod bearings and bore spacing in common with the longstanding Chevrolet small block V8 that preceded it as the basis for GM small-block V8s. The LS' basic layout owes a good deal to Ed Cole's original small-block design of 1954-55,[citation needed] though it also uses cues from Buick, Oldsmobile, and Pontiac V8s. The basic LS variations use cast iron blocks, while performance editions are all aluminum with cast iron cylinder liners.
The LS small-block has been manufactured in three Generations – III, IV, and V – with preceding Generations I and II of modular GM small-block engines having been based on the Chevrolet small-block V8 originally designed in 1955. GM recycled the "LT" designation previously used on Chevrolet small-block V8-derived "GM" engines beginning with the LS Generation V "LT1" in 2014.
Several versions of the LS were used in the Chevrolet Corvette, beginning with the LS1 in 1997 through the LS9 and others in 2013. Variants of the LT version of the GM small-block have been used since.
The LS based GM small-block engine is the primary V-8 used in General Motors' line of rear-wheel-drive cars and trucks. Introduced in January 1995, it is a "clean sheet" design with only rod bearings and bore spacing in common with the longstanding Chevrolet small block V8 that preceded it as the basis for GM small-block V8s. The LS' basic layout owes a good deal to Ed Cole's original small-block design of 1954-55,[citation needed] though it also uses cues from Buick, Oldsmobile, and Pontiac V8s. The basic LS variations use cast iron blocks, while performance editions are all aluminum with cast iron cylinder liners.
The LS small-block has been manufactured in three Generations – III, IV, and V – with preceding Generations I and II of modular GM small-block engines having been based on the Chevrolet small-block V8 originally designed in 1955. GM recycled the "LT" designation previously used on Chevrolet small-block V8-derived "GM" engines beginning with the LS Generation V "LT1" in 2014.
Several versions of the LS were used in the Chevrolet Corvette, beginning with the LS1 in 1997 through the LS9 and others in 2013. Variants of the LT version of the GM small-block have been used since.
Melting Slicks
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From: Central Florida
Burning Brakes
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Don't want to get into a pissing contest but if bore and stroke had no play why did they produce two different size blocks in the first place? Makes no sense to do that just to do that if not to accommodate different bore and stroke configurations. If you look it up you'll fnd the LONGEST stock stroke available on the LARGEST small block is 3.750 on the 400 cu in version. The SHORTEST stroke on the SMALLEST big block is 3.760 on the 366 cu in version. Those numbers for the 400 are the best GM could do without clearancing the block. You can now easily take a small block up to 468 cu in with off the shelf components but you will still need to clearance the block and limit camshaft duration to prevent the rod bolts from hitting it. Big blocks can can go well into the 700 cu in plus range. If "the bore and stroke had nothing to do with it" why don't we see small blocks with big block cu in numbers? For GM to make 2 different size blocks for purely aesthetic reasons is a little far fetched for me.
1/4 mile/AutoX
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From: Buffalo Texas
Don't want to get into a pissing contest but if bore and stroke had no play why did they produce two different size blocks in the first place? Makes no sense to do that just to do that if not to accommodate different bore and stroke configurations. If you look it up you'll fnd the LONGEST stock stroke available on the LARGEST small block is 3.750 on the 400 cu in version. The SHORTEST stroke on the SMALLEST big block is 3.760 on the 366 cu in version. Those numbers for the 400 are the best GM could do without clearancing the block. You can now easily take a small block up to 468 cu in with off the shelf components but you will still need to clearance the block and limit camshaft duration to prevent the rod bolts from hitting it. Big blocks can can go well into the 700 cu in plus range. If "the bore and stroke had nothing to do with it" why don't we see small blocks with big block cu in numbers? For GM to make 2 different size blocks for purely aesthetic reasons is a little far fetched for me.
Melting Slicks
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From: Central Florida
Don't want to get into a pissing contest but if bore and stroke had no play why did they produce two different size blocks in the first place? Makes no sense to do that just to do that if not to accommodate different bore and stroke configurations. If you look it up you'll fnd the LONGEST stock stroke available on the LARGEST small block is 3.750 on the 400 cu in version. The SHORTEST stroke on the SMALLEST big block is 3.760 on the 366 cu in version. Those numbers for the 400 are the best GM could do without clearancing the block. You can now easily take a small block up to 468 cu in with off the shelf components but you will still need to clearance the block and limit camshaft duration to prevent the rod bolts from hitting it. Big blocks can can go well into the 700 cu in plus range. If "the bore and stroke had nothing to do with it" why don't we see small blocks with big block cu in numbers? For GM to make 2 different size blocks for purely aesthetic reasons is a little far fetched for me.
and yes Im sure it was done to go big cubes and be strong.
Last edited by Forcedvert; Jan 8, 2017 at 11:38 AM.
Burning Brakes
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I'm sorry. I thought I was addressing the OP's question. I'm not lost on the concept of looking at the two and seeing one is bigger than the other but that's not the reason one was bigger than the other which is what I believe the OP asking. Maybe if they were a new design they would call them a Grande and a Venti. 
Burning Brakes
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From: Cedar Rapids IA
I'm sorry. I thought I was addressing the OP's question. I'm not lost on the concept of looking at the two and seeing one is bigger than the other but that's not the reason one was bigger than the other which is what I believe the OP asking. Maybe if they were a new design they would call them a Grande and a Venti.
big block == rat motor
small block == mouse motor
Burning Brakes
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From: Springfield IL.
Oldtimer
Don't want to get into a pissing contest but if bore and stroke had no play why did they produce two different size blocks in the first place? Makes no sense to do that just to do that if not to accommodate different bore and stroke configurations. If you look it up you'll fnd the LONGEST stock stroke available on the LARGEST small block is 3.750 on the 400 cu in version. The SHORTEST stroke on the SMALLEST big block is 3.760 on the 366 cu in version. Those numbers for the 400 are the best GM could do without clearancing the block. You can now easily take a small block up to 468 cu in with off the shelf components but you will still need to clearance the block and limit camshaft duration to prevent the rod bolts from hitting it. Big blocks can can go well into the 700 cu in plus range. If "the bore and stroke had nothing to do with it" why don't we see small blocks with big block cu in numbers? For GM to make 2 different size blocks for purely aesthetic reasons is a little far fetched for me.
You can't run a 5.7 or a 6.0 rod in one without a small base circle cam with even a 3.75 crank. I had a 6.0 rod 406 that produced 658 hp that seen 7500 rpm quite a few times, 7000 rpm shifts for 5 years and still ran great with over 500 passes. Sold out a couple years ago, got too old.
Last edited by 92GA; Jan 8, 2017 at 12:41 PM.
Burning Brakes
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1/4 mile/AutoX
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From: Buffalo Texas
Burning Brakes
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